diff --git a/annotated_gclient.py b/annotated_gclient.py
index f98500714..af5bcc5bd 100755
--- a/annotated_gclient.py
+++ b/annotated_gclient.py
@@ -41,7 +41,7 @@ def parse_got_revision(filename, revision_mapping):
   with open(filename) as f:
     data = json.load(f)
 
-  for path, info in data['solutions'].iteritems():
+  for path, info in data['solutions'].items():
     # gclient json paths always end with a slash
     path = path.rstrip('/')
     if path in revision_mapping:
@@ -52,7 +52,7 @@ def parse_got_revision(filename, revision_mapping):
 
 
 def emit_buildprops(got_revisions):
-  for prop, revision in got_revisions.iteritems():
+  for prop, revision in got_revisions.items():
     print('@@@SET_BUILD_PROPERTY@%s@%s@@@' % (prop, json.dumps(revision)))
 
 
diff --git a/autoninja b/autoninja
index cee4578d8..5dbcc5bac 100755
--- a/autoninja
+++ b/autoninja
@@ -5,7 +5,7 @@
 # found in the LICENSE file.
 
 # Set unique build ID.
-AUTONINJA_BUILD_ID="$(python -c "import uuid; print uuid.uuid4()")"
+AUTONINJA_BUILD_ID="$(python -c "import uuid; print(uuid.uuid4())")"
 export AUTONINJA_BUILD_ID
 
 if [ "$NINJA_SUMMARIZE_BUILD" == "1" ]; then
diff --git a/cpplint.py b/cpplint.py
index 04b99cbc4..d6c63df0a 100755
--- a/cpplint.py
+++ b/cpplint.py
@@ -908,7 +908,7 @@ class _CppLintState(object):
 
   def PrintErrorCounts(self):
     """Print a summary of errors by category, and the total."""
-    for category, count in self.errors_by_category.iteritems():
+    for category, count in self.errors_by_category.items():
       sys.stderr.write('Category \'%s\' errors found: %d\n' %
                        (category, count))
     sys.stderr.write('Total errors found: %d\n' % self.error_count)
@@ -4481,7 +4481,7 @@ def _GetTextInside(text, start_pattern):
 
   # Give opening punctuations to get the matching close-punctuations.
   matching_punctuation = {'(': ')', '{': '}', '[': ']'}
-  closing_punctuation = set(matching_punctuation.itervalues())
+  closing_punctuation = set(matching_punctuation.values())
 
   # Find the position to start extracting text.
   match = re.search(start_pattern, text, re.M)
diff --git a/gclient.py b/gclient.py
index 9bc33fda6..102cd43f1 100755
--- a/gclient.py
+++ b/gclient.py
@@ -590,7 +590,7 @@ class Dependency(gclient_utils.WorkItem, DependencySettings):
 
     # If a line is in custom_deps, but not in the solution, we want to append
     # this line to the solution.
-    for dep_name, dep_info in six.iteritems(self.custom_deps):
+    for dep_name, dep_info in self.custom_deps.items():
       if dep_name not in deps:
         deps[dep_name] = {'url': dep_info, 'dep_type': 'git'}
 
@@ -601,13 +601,13 @@ class Dependency(gclient_utils.WorkItem, DependencySettings):
     # recursively included by "src/ios_foo/DEPS" should also require
     # "checkout_ios=True".
     if self.condition:
-      for value in six.itervalues(deps):
+      for value in deps.values():
         gclient_eval.UpdateCondition(value, 'and', self.condition)
 
     if rel_prefix:
       logging.warning('use_relative_paths enabled.')
       rel_deps = {}
-      for d, url in six.iteritems(deps):
+      for d, url in deps.items():
         # normpath is required to allow DEPS to use .. in their
         # dependency local path.
         rel_deps[os.path.normpath(os.path.join(rel_prefix, d))] = url
@@ -619,7 +619,7 @@ class Dependency(gclient_utils.WorkItem, DependencySettings):
   def _deps_to_objects(self, deps, use_relative_paths):
     """Convert a deps dict to a dict of Dependency objects."""
     deps_to_add = []
-    for name, dep_value in six.iteritems(deps):
+    for name, dep_value in deps.items():
       should_process = self.should_process
       if dep_value is None:
         continue
@@ -727,7 +727,7 @@ class Dependency(gclient_utils.WorkItem, DependencySettings):
 
     self._vars = local_scope.get('vars', {})
     if self.parent:
-      for key, value in six.iteritems(self.parent.get_vars()):
+      for key, value in self.parent.get_vars().items():
         if key in self._vars:
           self._vars[key] = value
     # Since we heavily post-process things, freeze ones which should
@@ -764,7 +764,7 @@ class Dependency(gclient_utils.WorkItem, DependencySettings):
       if rel_prefix:
         logging.warning('Updating recursedeps by prepending %s.', rel_prefix)
         rel_deps = {}
-        for depname, options in six.iteritems(self.recursedeps):
+        for depname, options in self.recursedeps.items():
           rel_deps[
               os.path.normpath(os.path.join(rel_prefix, depname))] = options
         self.recursedeps = rel_deps
@@ -1600,7 +1600,7 @@ it or fix the checkout.
     full_entries = [os.path.join(self.root_dir, e.replace('/', os.path.sep))
                     for e in entries]
 
-    for entry, prev_url in six.iteritems(self._ReadEntries()):
+    for entry, prev_url in self._ReadEntries().items():
       if not prev_url:
         # entry must have been overridden via .gclient custom_deps
         continue
@@ -1747,7 +1747,7 @@ it or fix the checkout.
           'The following --patch-ref flags were not used. Please fix it:\n%s' %
           ('\n'.join(
               patch_repo + '@' + patch_ref
-              for patch_repo, patch_ref in six.iteritems(patch_refs))))
+              for patch_repo, patch_ref in patch_refs.items())))
 
     # Once all the dependencies have been processed, it's now safe to write
     # out the gn_args_file and run the hooks.
@@ -1834,7 +1834,7 @@ it or fix the checkout.
                 'url': rev.split('@')[0] if rev else None,
                 'rev': rev.split('@')[1] if rev and '@' in rev else None,
             }
-            for name, rev in six.iteritems(entries)
+            for name, rev in entries.items()
         }
         if self._options.output_json == '-':
           print(json.dumps(json_output, indent=2, separators=(',', ': ')))
@@ -2122,7 +2122,7 @@ class Flattener(object):
       self._flatten_dep(solution)
 
     if pin_all_deps:
-      for dep in six.itervalues(self._deps):
+      for dep in self._deps.values():
         self._pin_dep(dep)
 
     def add_deps_file(dep):
@@ -2140,7 +2140,7 @@ class Flattener(object):
           return
       assert dep.url
       self._deps_files.add((dep.url, deps_file, dep.hierarchy_data()))
-    for dep in six.itervalues(self._deps):
+    for dep in self._deps.values():
       add_deps_file(dep)
 
     gn_args_dep = self._deps.get(self._client.dependencies[0]._gn_args_from,
@@ -2183,7 +2183,7 @@ class Flattener(object):
     # Only include vars explicitly listed in the DEPS files or gclient solution,
     # not automatic, local overrides (i.e. not all of dep.get_vars()).
     hierarchy = dep.hierarchy(include_url=False)
-    for key, value in six.iteritems(dep._vars):
+    for key, value in dep._vars.items():
       # Make sure there are no conflicting variables. It is fine however
       # to use same variable name, as long as the value is consistent.
       assert key not in self._vars or self._vars[key][1] == value, (
@@ -2191,7 +2191,7 @@ class Flattener(object):
           dep.name, key, value, self._vars[key][1]))
       self._vars[key] = (hierarchy, value)
     # Override explicit custom variables.
-    for key, value in six.iteritems(dep.custom_vars):
+    for key, value in dep.custom_vars.items():
       # Do custom_vars that don't correspond to DEPS vars ever make sense? DEPS
       # conditionals shouldn't be using vars that aren't also defined in the
       # DEPS (presubmit actually disallows this), so any new custom_var must be
@@ -2344,7 +2344,7 @@ def _HooksOsToLines(hooks_os):
   if not hooks_os:
     return []
   s = ['hooks_os = {']
-  for hook_os, os_hooks in six.iteritems(hooks_os):
+  for hook_os, os_hooks in hooks_os.items():
     s.append('  "%s": [' % hook_os)
     for dep, hook in os_hooks:
       s.extend([
diff --git a/gclient_eval.py b/gclient_eval.py
index 66656ae86..002ebb45d 100644
--- a/gclient_eval.py
+++ b/gclient_eval.py
@@ -52,7 +52,7 @@ class _NodeDict(collections.MutableMapping):
   def MoveTokens(self, origin, delta):
     if self.tokens:
       new_tokens = {}
-      for pos, token in six.iteritems(self.tokens):
+      for pos, token in self.tokens.items():
         if pos[0] >= origin:
           pos = (pos[0] + delta, pos[1])
           token = token[:2] + (pos,) + token[3:]
@@ -509,14 +509,14 @@ def Parse(content, validate_syntax, filename, vars_override=None,
 
   if 'deps_os' in result:
     deps = result.setdefault('deps', {})
-    for os_name, os_deps in six.iteritems(result['deps_os']):
+    for os_name, os_deps in result['deps_os'].items():
       os_deps = _StandardizeDeps(os_deps, vars_dict)
       _MergeDepsOs(deps, os_deps, os_name)
     del result['deps_os']
 
   if 'hooks_os' in result:
     hooks = result.setdefault('hooks', [])
-    for os_name, os_hooks in six.iteritems(result['hooks_os']):
+    for os_name, os_hooks in result['hooks_os'].items():
       for hook in os_hooks:
         UpdateCondition(hook, 'and', 'checkout_' + os_name)
       hooks.extend(os_hooks)
diff --git a/gclient_utils.py b/gclient_utils.py
index dde73def6..5e609ed97 100644
--- a/gclient_utils.py
+++ b/gclient_utils.py
@@ -1229,7 +1229,7 @@ class FrozenDict(collections.Mapping):
       return True
     if len(self) != len(other):
       return False
-    for k, v in self.iteritems():
+    for k, v in self.items():
       if k not in other or other[k] != v:
         return False
     return True
diff --git a/gerrit_util.py b/gerrit_util.py
index 9e694cf37..21ec65bea 100644
--- a/gerrit_util.py
+++ b/gerrit_util.py
@@ -238,7 +238,7 @@ class CookiesAuthenticator(Authenticator):
     return gitcookies
 
   def _get_auth_for_host(self, host):
-    for domain, creds in self.gitcookies.iteritems():
+    for domain, creds in self.gitcookies.items():
       if cookielib.domain_match(host, domain):
         return (creds[0], None, creds[1])
     return self.netrc.authenticators(host)
@@ -386,7 +386,7 @@ def CreateHttpConn(host, path, reqtype='GET', headers=None, body=None):
     headers.setdefault('Content-Type', 'application/json')
   if LOGGER.isEnabledFor(logging.DEBUG):
     LOGGER.debug('%s %s://%s%s' % (reqtype, GERRIT_PROTOCOL, host, url))
-    for key, val in headers.iteritems():
+    for key, val in headers.items():
       if key == 'Authorization':
         val = 'HIDDEN'
       LOGGER.debug('%s: %s' % (key, val))
@@ -798,7 +798,7 @@ def AddReviewers(host, change, reviewers=None, ccs=None, notify=True,
   resp = ReadHttpJsonResponse(conn, accept_statuses=accept_statuses)
 
   errored = set()
-  for result in resp.get('reviewers', {}).itervalues():
+  for result in resp.get('reviewers', {}).values():
     r = result.get('input')
     state = 'REVIEWER' if r in reviewers else 'CC'
     if result.get('error'):
@@ -845,7 +845,7 @@ def SetReview(host, change, msg=None, labels=None, notify=None, ready=None):
   conn = CreateHttpConn(host, path, reqtype='POST', body=body)
   response = ReadHttpJsonResponse(conn)
   if labels:
-    for key, val in labels.iteritems():
+    for key, val in labels.items():
       if ('labels' not in response or key not in response['labels'] or
           int(response['labels'][key] != int(val))):
         raise GerritError(200, 'Unable to set "%s" label on change %s.' % (
diff --git a/git_cl.py b/git_cl.py
index e79490b73..39c6c5ee8 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -315,7 +315,7 @@ def _git_set_branch_config_value(key, value, branch=None, **kwargs):
 def _get_properties_from_options(options):
   prop_list = getattr(options, 'properties', [])
   properties = dict(x.split('=', 1) for x in prop_list)
-  for key, val in properties.iteritems():
+  for key, val in properties.items():
     try:
       properties[key] = json.loads(val)
     except ValueError:
@@ -415,7 +415,7 @@ def _get_bucket_map(changelist, options, option_parser):
         output_stream=sys.stdout)
     if masters is None:
       return None
-    return {m: b for m, b in masters.iteritems()}
+    return {m: b for m, b in masters.items()}
 
   if options.bucket:
     return {options.bucket: {b: [] for b in options.bot}}
@@ -452,11 +452,11 @@ def _trigger_try_jobs(auth_config, changelist, buckets, options, patchset):
     options: Command-line options.
   """
   print('Scheduling jobs on:')
-  for bucket, builders_and_tests in sorted(buckets.iteritems()):
+  for bucket, builders_and_tests in sorted(buckets.items()):
     print('Bucket:', bucket)
     print('\n'.join(
         '  %s: %s' % (builder, tests)
-        for builder, tests in sorted(builders_and_tests.iteritems())))
+        for builder, tests in sorted(builders_and_tests.items())))
   print('To see results here, run:        git cl try-results')
   print('To see results in browser, run:  git cl web')
 
@@ -495,13 +495,13 @@ def _make_try_job_schedule_requests(changelist, buckets, options, patchset):
                         'value': '1'})
 
   requests = []
-  for raw_bucket, builders_and_tests in sorted(buckets.iteritems()):
+  for raw_bucket, builders_and_tests in sorted(buckets.items()):
     project, bucket = _parse_bucket(raw_bucket)
     if not project or not bucket:
       print('WARNING Could not parse bucket "%s". Skipping.' % raw_bucket)
       continue
 
-    for builder, tests in sorted(builders_and_tests.iteritems()):
+    for builder, tests in sorted(builders_and_tests.items()):
       properties = shared_properties.copy()
       if 'presubmit' in builder.lower():
         properties['dry_run'] = 'true'
@@ -1874,7 +1874,7 @@ class Changelist(object):
     # Add the robot comments onto the list of comments, but only
     # keep those that are from the latest patchset.
     latest_patch_set = self.GetMostRecentPatchset()
-    for path, robot_comments in robot_file_comments.iteritems():
+    for path, robot_comments in robot_file_comments.items():
       line_comments = file_comments.setdefault(path, [])
       line_comments.extend(
           [c for c in robot_comments if c['patch_set'] == latest_patch_set])
@@ -1883,7 +1883,7 @@ class Changelist(object):
     # {author+date: {path: {patchset: {line: url+message}}}}
     comments = collections.defaultdict(
         lambda: collections.defaultdict(lambda: collections.defaultdict(dict)))
-    for path, line_comments in file_comments.iteritems():
+    for path, line_comments in file_comments.items():
       for comment in line_comments:
         tag = comment.get('tag', '')
         if tag.startswith('autogenerated') and 'robot_id' not in comment:
@@ -2095,7 +2095,7 @@ class Changelist(object):
       patchset = int(revision_info['_number'])
     else:
       patchset = parsed_issue_arg.patchset
-      for revision_info in detail['revisions'].itervalues():
+      for revision_info in detail['revisions'].values():
         if int(revision_info['_number']) == parsed_issue_arg.patchset:
           break
       else:
@@ -2672,7 +2672,7 @@ class Changelist(object):
 
     has_patchset = any(
         int(revision_data['_number']) == patchset
-        for revision_data in data['revisions'].itervalues())
+        for revision_data in data['revisions'].values())
     if not has_patchset:
       raise Exception('Patchset %d is not known in Gerrit change %d' %
                       (patchset, self.GetIssue()))
@@ -3246,8 +3246,8 @@ class _GitCookiesChecker(object):
       self._all_hosts = [
           (h, u, s)
           for h, u, s in itertools.chain(
-              ((h, u, '.netrc') for h, (u, _, _) in a.netrc.hosts.iteritems()),
-              ((h, u, '.gitcookies') for h, (u, _) in a.gitcookies.iteritems())
+              ((h, u, '.netrc') for h, (u, _, _) in a.netrc.hosts.items()),
+              ((h, u, '.gitcookies') for h, (u, _) in a.gitcookies.items())
           )
           if h.endswith(self._GOOGLESOURCE)
       ]
@@ -3328,18 +3328,18 @@ class _GitCookiesChecker(object):
   def get_partially_configured_hosts(self):
     return set(
         (host if i1 else self._canonical_gerrit_googlesource_host(host))
-        for host, (i1, i2) in self._get_git_gerrit_identity_pairs().iteritems()
+        for host, (i1, i2) in self._get_git_gerrit_identity_pairs().items()
         if None in (i1, i2) and host != '.' + self._GOOGLESOURCE)
 
   def get_conflicting_hosts(self):
     return set(
         host
-        for host, (i1, i2) in self._get_git_gerrit_identity_pairs().iteritems()
+        for host, (i1, i2) in self._get_git_gerrit_identity_pairs().items()
         if None not in (i1, i2) and i1 != i2)
 
   def get_duplicated_hosts(self):
     counters = collections.Counter(h for h, _, _ in self.get_hosts_with_creds())
-    return set(host for host, count in counters.iteritems() if count > 1)
+    return set(host for host, count in counters.items() if count > 1)
 
   _EXPECTED_HOST_IDENTITY_DOMAINS = {
     'chromium.googlesource.com': 'chromium.org',
@@ -3352,7 +3352,7 @@ class _GitCookiesChecker(object):
     Note: skips hosts which have conflicting identities for Git and Gerrit.
     """
     hosts = set()
-    for host, expected in self._EXPECTED_HOST_IDENTITY_DOMAINS.iteritems():
+    for host, expected in self._EXPECTED_HOST_IDENTITY_DOMAINS.items():
       pair = self._get_git_gerrit_identity_pairs().get(host)
       if pair and pair[0] == pair[1]:
         _, domain = self._parse_identity(pair[0])
@@ -4722,7 +4722,7 @@ def CMDtry(parser, args):
       print('There are no failed jobs in the latest set of jobs '
             '(patchset #%d), doing nothing.' % patchset)
       return 0
-    num_builders = sum(map(len, buckets.itervalues()))
+    num_builders = sum(map(len, buckets.values()))
     if num_builders > 10:
       confirm_or_exit('There are %d builders with failed builds.'
                       % num_builders, action='continue')
@@ -4740,7 +4740,7 @@ def CMDtry(parser, args):
     print('Scheduling CQ dry run on: %s' % cl.GetIssueURL())
     return cl.SetCQState(_CQState.DRY_RUN)
 
-  for builders in buckets.itervalues():
+  for builders in buckets.values():
     if any('triggered' in b for b in builders):
       print('ERROR You are trying to send a job to a triggered bot. This type '
             'of bot requires an initial job from a parent (usually a builder). '
diff --git a/git_map.py b/git_map.py
index 278cfbe7c..f76d0dff1 100755
--- a/git_map.py
+++ b/git_map.py
@@ -77,7 +77,7 @@ def main(argv):
   current = current_branch()
   all_branches = set(branches())
   merge_base_map = {b: get_or_create_merge_base(b) for b in all_branches}
-  merge_base_map = {b: v for b, v in merge_base_map.iteritems() if v}
+  merge_base_map = {b: v for b, v in merge_base_map.items() if v}
   if current in all_branches:
     all_branches.remove(current)
   all_tags = set(tags())
@@ -86,7 +86,7 @@ def main(argv):
       if merge_base_map:
         commit = line[line.find(BRIGHT_RED)+len(BRIGHT_RED):line.find('\t')]
         base_for_branches = set()
-        for branch, sha in merge_base_map.iteritems():
+        for branch, sha in merge_base_map.items():
           if sha.startswith(commit):
             base_for_branches.add(branch)
         if base_for_branches:
diff --git a/git_map_branches.py b/git_map_branches.py
index 60cf317b2..55d574b53 100755
--- a/git_map_branches.py
+++ b/git_map_branches.py
@@ -147,7 +147,7 @@ class BranchMapper(object):
     roots = set()
 
     # A map of parents to a list of their children.
-    for branch, branch_info in self.__branches_info.iteritems():
+    for branch, branch_info in self.__branches_info.items():
       if not branch_info:
         continue
 
diff --git a/git_rebase_update.py b/git_rebase_update.py
index e1d6b2222..a559d072a 100755
--- a/git_rebase_update.py
+++ b/git_rebase_update.py
@@ -57,12 +57,12 @@ def fetch_remotes(branch_tree):
     dest_spec = fetchspec.partition(':')[2]
     remote_name = key.split('.')[1]
     fetchspec_map[dest_spec] = remote_name
-  for parent in branch_tree.itervalues():
+  for parent in branch_tree.values():
     if parent in tag_set:
       fetch_tags = True
     else:
       full_ref = git.run('rev-parse', '--symbolic-full-name', parent)
-      for dest_spec, remote_name in fetchspec_map.iteritems():
+      for dest_spec, remote_name in fetchspec_map.items():
         if fnmatch(full_ref, dest_spec):
           remotes.add(remote_name)
           break
@@ -121,7 +121,7 @@ def remove_empty_branches(branch_tree):
           reparents[down] = (order, parent, old_parent)
 
   # Apply all reparenting recorded, in order.
-  for branch, value in sorted(reparents.iteritems(), key=lambda x:x[1][0]):
+  for branch, value in sorted(reparents.items(), key=lambda x:x[1][0]):
     _, parent, old_parent = value
     if parent in tag_set:
       git.set_branch_config(branch, 'remote', '.')
@@ -134,7 +134,7 @@ def remove_empty_branches(branch_tree):
                                                              old_parent))
 
   # Apply all deletions recorded, in order.
-  for branch, _ in sorted(deletions.iteritems(), key=lambda x: x[1]):
+  for branch, _ in sorted(deletions.items(), key=lambda x: x[1]):
     print(git.run('branch', '-d', branch))
 
 
@@ -272,7 +272,7 @@ def main(args=None):
     fetch_remotes(branch_tree)
 
   merge_base = {}
-  for branch, parent in branch_tree.iteritems():
+  for branch, parent in branch_tree.items():
     merge_base[branch] = git.get_or_create_merge_base(branch, parent)
 
   logging.debug('branch_tree: %s' % pformat(branch_tree))
diff --git a/git_rename_branch.py b/git_rename_branch.py
index c0ac42ec1..8a07535f7 100755
--- a/git_rename_branch.py
+++ b/git_rename_branch.py
@@ -36,7 +36,7 @@ def main(args):
     run('branch', '-m', opts.old_name, opts.new_name)
 
     # update the downstreams
-    for branch, merge in branch_config_map('merge').iteritems():
+    for branch, merge in branch_config_map('merge').items():
       if merge == 'refs/heads/' + opts.old_name:
         # Only care about local branches
         if branch_config(branch, 'remote') == '.':
diff --git a/man/src/common_demo_functions.sh b/man/src/common_demo_functions.sh
index 7501f5a5a..cfb26a083 100755
--- a/man/src/common_demo_functions.sh
+++ b/man/src/common_demo_functions.sh
@@ -37,7 +37,7 @@ praw() {
 pcommand() {
   praw "$(python -c '\
     import sys, pipes; \
-    print " ".join(map(pipes.quote, sys.argv[1:]))' "$@")"
+    print(" ".join(map(pipes.quote, sys.argv[1:])))' "$@")"
 }
 
 # run a visible command
@@ -71,7 +71,7 @@ add() {
   if [[ ! $CONTENT ]]
   then
     CONTENT=$(python -c 'import random, string; \
-      print "".join(random.sample(string.lowercase, 16))')
+      print("".join(random.sample(string.lowercase, 16)))')
   fi
   echo "$CONTENT" > $1
   silent git add $1
diff --git a/my_activity.py b/my_activity.py
index 81b901d0a..5620ca10d 100755
--- a/my_activity.py
+++ b/my_activity.py
@@ -603,7 +603,7 @@ class MyActivity(object):
       project, issue_id = issue_uid.split(':')
       missing_issues_by_project[project].append(issue_id)
 
-    for project, issue_ids in missing_issues_by_project.iteritems():
+    for project, issue_ids in missing_issues_by_project.items():
       self.referenced_issues += self.monorail_get_issues(project, issue_ids)
 
   def print_issues(self):
@@ -676,7 +676,7 @@ class MyActivity(object):
         if not url:
           raise Exception('Dumped item %s does not specify url' % item)
         output[url] = dict(
-            (k, v) for k,v in item.iteritems() if k not in ignore_keys)
+            (k, v) for k,v in item.items() if k not in ignore_keys)
       return output
 
     class PythonObjectEncoder(json.JSONEncoder):
diff --git a/owners.py b/owners.py
index b8578023c..8c503f12c 100644
--- a/owners.py
+++ b/owners.py
@@ -271,7 +271,7 @@ class Database(object):
     while True:
       dir_owner_rules = self._paths_to_owners.get(dirname)
       if dir_owner_rules:
-        for owned_path, path_owners in dir_owner_rules.iteritems():
+        for owned_path, path_owners in dir_owner_rules.items():
           if self._fnmatch(objname, owned_path):
             obj_owners |= path_owners
       up_dirname = self.os_path.dirname(dirname)
@@ -539,7 +539,7 @@ class Database(object):
         # Merge the parent information with our information, adjusting
         # distances as necessary, and replacing the parent directory
         # names with our names.
-        for owner, par_dir_and_distances in parent_res.iteritems():
+        for owner, par_dir_and_distances in parent_res.items():
           if owner in res:
             # If the same person is in multiple OWNERS files above a given
             # directory, only count the closest one.
@@ -564,7 +564,7 @@ class Database(object):
       dir_owners = self._all_possible_owners_for_dir_or_file(
         current_dir, author,
         all_possible_owners_for_dir_or_file_cache)
-      for owner, dir_and_distance in dir_owners.iteritems():
+      for owner, dir_and_distance in dir_owners.items():
           if owner in all_possible_owners:
             all_possible_owners[owner].append(dir_and_distance)
           else:
@@ -605,7 +605,7 @@ class Database(object):
     total_costs_by_owner = Database.total_costs_by_owner(all_possible_owners,
                                                          dirs)
     # Return the lowest cost owner. In the case of a tie, pick one randomly.
-    lowest_cost = min(total_costs_by_owner.itervalues())
+    lowest_cost = min(total_costs_by_owner.values())
     lowest_cost_owners = filter(
         lambda owner: total_costs_by_owner[owner] == lowest_cost,
         total_costs_by_owner)
diff --git a/presubmit_canned_checks.py b/presubmit_canned_checks.py
index 2b559af7e..22599a00e 100644
--- a/presubmit_canned_checks.py
+++ b/presubmit_canned_checks.py
@@ -949,7 +949,7 @@ def CheckBuildbotPendingBuilds(input_api, output_api, url, max_pendings,
                                              'looking up buildbot status')]
 
   out = []
-  for (builder_name, builder) in data.iteritems():
+  for (builder_name, builder) in data.items():
     if builder_name in ignored:
       continue
     if builder.get('state', '') == 'offline':
@@ -1326,7 +1326,7 @@ def CheckCIPDPackages(input_api, output_api, platforms, packages):
   manifest = []
   for p in platforms:
     manifest.append('$VerifiedPlatform %s' % (p,))
-  for k, v in packages.iteritems():
+  for k, v in packages.items():
     manifest.append('%s %s' % (k, v))
   return CheckCIPDManifest(input_api, output_api, content='\n'.join(manifest))
 
@@ -1468,7 +1468,7 @@ def CheckChangedLUCIConfigs(input_api, output_api):
     # windows
     file_path = f.LocalPath().replace(_os.sep, '/')
     logging.debug('Affected file path: %s', file_path)
-    for dr, cs in dir_to_config_set.iteritems():
+    for dr, cs in dir_to_config_set.items():
       if dr == '/' or file_path.startswith(dr):
         cs_to_files[cs].append({
           'path': file_path[len(dr):] if dr != '/' else file_path,
@@ -1476,7 +1476,7 @@ def CheckChangedLUCIConfigs(input_api, output_api):
               '\n'.join(f.NewContents()).encode('utf-8'))
         })
   outputs = []
-  for cs, f in cs_to_files.iteritems():
+  for cs, f in cs_to_files.items():
     try:
       # TODO(myjang): parallelize
       res = request(
diff --git a/presubmit_support.py b/presubmit_support.py
index 672f5e736..bdf9fd640 100755
--- a/presubmit_support.py
+++ b/presubmit_support.py
@@ -386,7 +386,7 @@ class GerritAccessor(object):
 
     # Find revision info for the patchset we want.
     if patchset is not None:
-      for rev, rev_info in info['revisions'].iteritems():
+      for rev, rev_info in info['revisions'].items():
         if str(rev_info['_number']) == str(patchset):
           break
       else:
@@ -1279,10 +1279,10 @@ class GetPostUploadExecuter(object):
 def _MergeMasters(masters1, masters2):
   """Merges two master maps. Merges also the tests of each builder."""
   result = {}
-  for (master, builders) in itertools.chain(masters1.iteritems(),
-                                            masters2.iteritems()):
+  for (master, builders) in itertools.chain(masters1.items(),
+                                            masters2.items()):
     new_builders = result.setdefault(master, {})
-    for (builder, tests) in builders.iteritems():
+    for (builder, tests) in builders.items():
       new_builders.setdefault(builder, set([])).update(tests)
   return result
 
@@ -1329,7 +1329,7 @@ def DoGetTryMasters(change,
         presubmit_script, filename, project, change))
 
   # Make sets to lists again for later JSON serialization.
-  for builders in results.itervalues():
+  for builders in results.values():
     for builder in builders:
       builders[builder] = list(builders[builder])
 
@@ -1659,7 +1659,7 @@ def canned_check_filter(method_names):
       setattr(presubmit_canned_checks, method_name, lambda *_a, **_kw: [])
     yield
   finally:
-    for name, method in filtered.iteritems():
+    for name, method in filtered.items():
       setattr(presubmit_canned_checks, name, method)
 
 
diff --git a/recipes/recipe_modules/bot_update/api.py b/recipes/recipe_modules/bot_update/api.py
index 715bb24f4..200da9642 100644
--- a/recipes/recipe_modules/bot_update/api.py
+++ b/recipes/recipe_modules/bot_update/api.py
@@ -183,7 +183,7 @@ class BotUpdateApi(recipe_api.RecipeApi):
       # Only update with non-empty values. Some recipe might otherwise
       # overwrite the HEAD default with an empty string.
       revisions.update(
-          (k, v) for k, v in cfg.revisions.iteritems() if v)
+          (k, v) for k, v in cfg.revisions.items() if v)
     if cfg.solutions and root_solution_revision:
       revisions[first_sol] = root_solution_revision
     # Allow for overrides required to bisect into rolls.
@@ -275,7 +275,7 @@ class BotUpdateApi(recipe_api.RecipeApi):
         if update_presentation:
           # Set properties such as got_revision.
           for prop_name, prop_value in (
-              self.last_returned_properties.iteritems()):
+              self.last_returned_properties.items()):
             step_result.presentation.properties[prop_name] = prop_value
 
         # Add helpful step description in the step UI.
@@ -471,7 +471,7 @@ class BotUpdateApi(recipe_api.RecipeApi):
     rev_reverse_map = self.m.gclient.got_revision_reverse_mapping(cfg)
     return sorted(
         prop
-        for prop, project in rev_reverse_map.iteritems()
+        for prop, project in rev_reverse_map.items()
         if project == project_name
     )
 
diff --git a/recipes/recipe_modules/bot_update/resources/bot_update.py b/recipes/recipe_modules/bot_update/resources/bot_update.py
index 03a2f60b4..9eaeb5976 100755
--- a/recipes/recipe_modules/bot_update/resources/bot_update.py
+++ b/recipes/recipe_modules/bot_update/resources/bot_update.py
@@ -5,6 +5,8 @@
 
 # TODO(hinoka): Use logging.
 
+from __future__ import print_function
+
 import cStringIO
 import codecs
 from contextlib import contextmanager
@@ -147,11 +149,11 @@ def call(*args, **kwargs):  # pragma: no cover
   kwargs['env'] = env
 
   if new_env:
-    print '===Injecting Environment Variables==='
+    print('===Injecting Environment Variables===')
     for k, v in sorted(new_env.items()):
-      print '%s: %s' % (k, v)
-  print '===Running %s ===' % (' '.join(args),)
-  print 'In directory: %s' % cwd
+      print('%s: %s' % (k, v))
+  print('===Running %s ===' % (' '.join(args),))
+  print('In directory: %s' % cwd)
   start_time = time.time()
   proc = subprocess.Popen(args, **kwargs)
   if stdin_data:
@@ -183,14 +185,14 @@ def call(*args, **kwargs):  # pragma: no cover
   elapsed_time = ((time.time() - start_time) / 60.0)
   outval = out.getvalue()
   if code:
-    print '===Failed in %.1f mins of %s ===' % (elapsed_time, ' '.join(args))
-    print
+    print('===Failed in %.1f mins of %s ===' % (elapsed_time, ' '.join(args)))
+    print()
     raise SubprocessFailed('%s failed with code %d in %s.' %
                            (' '.join(args), code, cwd),
                            code, outval)
 
-  print '===Succeeded in %.1f mins of %s ===' % (elapsed_time, ' '.join(args))
-  print
+  print('===Succeeded in %.1f mins of %s ===' % (elapsed_time, ' '.join(args)))
+  print()
   return outval
 
 
@@ -222,36 +224,36 @@ def get_gclient_spec(solutions, target_os, target_os_only, target_cpu,
 
 def solutions_printer(solutions):
   """Prints gclient solution to stdout."""
-  print 'Gclient Solutions'
-  print '================='
+  print('Gclient Solutions')
+  print('=================')
   for solution in solutions:
     name = solution.get('name')
     url = solution.get('url')
-    print '%s (%s)' % (name, url)
+    print('%s (%s)' % (name, url))
     if solution.get('deps_file'):
-      print '  Dependencies file is %s' % solution['deps_file']
+      print('  Dependencies file is %s' % solution['deps_file'])
     if 'managed' in solution:
-      print '  Managed mode is %s' % ('ON' if solution['managed'] else 'OFF')
+      print('  Managed mode is %s' % ('ON' if solution['managed'] else 'OFF'))
     custom_vars = solution.get('custom_vars')
     if custom_vars:
-      print '  Custom Variables:'
-      for var_name, var_value in sorted(custom_vars.iteritems()):
-        print '    %s = %s' % (var_name, var_value)
+      print('  Custom Variables:')
+      for var_name, var_value in sorted(custom_vars.items()):
+        print('    %s = %s' % (var_name, var_value))
     custom_deps = solution.get('custom_deps')
     if 'custom_deps' in solution:
-      print '  Custom Dependencies:'
-      for deps_name, deps_value in sorted(custom_deps.iteritems()):
+      print('  Custom Dependencies:')
+      for deps_name, deps_value in sorted(custom_deps.items()):
         if deps_value:
-          print '    %s -> %s' % (deps_name, deps_value)
+          print('    %s -> %s' % (deps_name, deps_value))
         else:
-          print '    %s: Ignore' % deps_name
-    for k, v in solution.iteritems():
+          print('    %s: Ignore' % deps_name)
+    for k, v in solution.items():
       # Print out all the keys we don't know about.
       if k in ['name', 'url', 'deps_file', 'custom_vars', 'custom_deps',
                'managed']:
         continue
-      print '  %s is %s' % (k, v)
-    print
+      print('  %s is %s' % (k, v))
+    print()
 
 
 def modify_solutions(input_solutions):
@@ -270,8 +272,8 @@ def modify_solutions(input_solutions):
     # We don't want gclient to be using a safesync URL. Instead it should
     # using the lkgr/lkcr branch/tags.
     if 'safesync_url' in solution:
-      print 'Removing safesync url %s from %s' % (solution['safesync_url'],
-                                                  parsed_path)
+      print('Removing safesync url %s from %s' % (solution['safesync_url'],
+                                                  parsed_path))
       del solution['safesync_url']
 
   return solutions
@@ -283,11 +285,11 @@ def remove(target, cleanup_dir):
     os.makedirs(cleanup_dir)
   dest = path.join(cleanup_dir, '%s_%s' % (
       path.basename(target), uuid.uuid4().hex))
-  print 'Marking for removal %s => %s' % (target, dest)
+  print('Marking for removal %s => %s' % (target, dest))
   try:
     os.rename(target, dest)
   except Exception as e:
-    print 'Error renaming %s to %s: %s' % (target, dest, str(e))
+    print('Error renaming %s to %s: %s' % (target, dest, str(e)))
     raise
 
 
@@ -299,9 +301,9 @@ def ensure_no_checkout(dir_names, cleanup_dir):
   if has_checkout:
     for filename in os.listdir(build_dir):
       deletion_target = path.join(build_dir, filename)
-      print '.git detected in checkout, deleting %s...' % deletion_target,
+      print('.git detected in checkout, deleting %s...' % deletion_target,)
       remove(deletion_target, cleanup_dir)
-      print 'done'
+      print('done')
 
 
 def call_gclient(*args, **kwargs):
@@ -363,7 +365,7 @@ def gclient_sync(
     args += ['--break_repo_locks']
   if disable_syntax_validation:
     args += ['--disable-syntax-validation']
-  for name, revision in sorted(revisions.iteritems()):
+  for name, revision in sorted(revisions.items()):
     if revision.upper() == 'HEAD':
       revision = 'origin/master'
     args.extend(['--revision', '%s@%s' % (name, revision)])
@@ -432,7 +434,7 @@ def create_manifest_old():
         'revision': match.group(3),
       }
     else:
-      print "WARNING: Couldn't match revinfo line:\n%s" % line
+      print("WARNING: Couldn't match revinfo line:\n%s" % line)
   return manifest
 
 
@@ -456,7 +458,7 @@ def create_manifest(gclient_output, patch_root):
   dirs = {}
   if patch_root:
     patch_root = patch_root.strip('/')  # Normalize directory names.
-  for directory, info in gclient_output.get('solutions', {}).iteritems():
+  for directory, info in gclient_output.get('solutions', {}).items():
     directory = directory.strip('/')  # Normalize the directory name.
     # The format of the url is "https://repo.url/blah.git@abcdefabcdef" or
     # just "https://repo.url/blah.git"
@@ -617,11 +619,11 @@ def _maybe_break_locks(checkout_path, tries=3):
       for filename in filenames:
         if filename.endswith('.lock'):
           to_break = os.path.join(dirpath, filename)
-          print 'breaking lock: %s' % to_break
+          print('breaking lock: %s' % to_break)
           try:
             os.remove(to_break)
           except OSError as ex:
-            print 'FAILED to break lock: %s: %s' % (to_break, ex)
+            print('FAILED to break lock: %s: %s' % (to_break, ex))
             raise
 
   for _ in xrange(tries):
@@ -688,14 +690,14 @@ def _git_checkout(sln, sln_dir, revisions, refs, git_cache_dir, cleanup_dir):
       # Only kick in deadline after second attempt to ensure we retry at least
       # once after initial fetch from not-yet-replicated server.
       if attempt >= 2 and overrun > 0:
-        print 'Ran %s seconds past deadline. Aborting.' % (overrun,)
+        print('Ran %s seconds past deadline. Aborting.' % (overrun,))
         # TODO(tandrii): raise exception immediately here, instead of doing
         # useless step 2 trying to fetch something that we know doesn't exist
         # in cache **after production data gives us confidence to do so**.
         break
 
       sleep_secs = min(60, 2**attempt)
-      print 'waiting %s seconds and trying to fetch again...' % sleep_secs
+      print('waiting %s seconds and trying to fetch again...' % sleep_secs)
       time.sleep(sleep_secs)
 
   # Step 2: populate a checkout from local cache. All operations are local.
@@ -707,7 +709,7 @@ def _git_checkout(sln, sln_dir, revisions, refs, git_cache_dir, cleanup_dir):
       # If repo deletion was aborted midway, it may have left .git in broken
       # state.
       if path.exists(sln_dir) and is_broken_repo_dir(sln_dir):
-        print 'Git repo %s appears to be broken, removing it' % sln_dir
+        print('Git repo %s appears to be broken, removing it' % sln_dir)
         remove(sln_dir, cleanup_dir)
 
       # Use "tries=1", since we retry manually in this loop.
@@ -735,7 +737,7 @@ def _git_checkout(sln, sln_dir, revisions, refs, git_cache_dir, cleanup_dir):
       return
     except SubprocessFailed as e:
       # Exited abnormally, theres probably something wrong.
-      print 'Something failed: %s.' % str(e)
+      print('Something failed: %s.' % str(e))
       if first_try:
         first_try = False
         # Lets wipe the checkout and try again.
@@ -783,9 +785,9 @@ def parse_got_revision(gclient_output, got_revision_mapping):
   solutions_output = {
       # Make sure path always ends with a single slash.
       '%s/' % path.rstrip('/') : solution_output for path, solution_output
-      in gclient_output['solutions'].iteritems()
+      in gclient_output['solutions'].items()
   }
-  for property_name, dir_name in got_revision_mapping.iteritems():
+  for property_name, dir_name in got_revision_mapping.items():
     # Make sure dir_name always ends with a single slash.
     dir_name = '%s/' % dir_name.rstrip('/')
     if dir_name not in solutions_output:
@@ -824,7 +826,7 @@ def ensure_checkout(solutions, revisions, first_sln, target_os, target_os_only,
   # Get a checkout of each solution, without DEPS or hooks.
   # Calling git directly because there is no way to run Gclient without
   # invoking DEPS.
-  print 'Fetching Git checkout'
+  print('Fetching Git checkout')
 
   git_checkouts(solutions, revisions, refs, git_cache_dir, cleanup_dir)
 
@@ -838,7 +840,7 @@ def ensure_checkout(solutions, revisions, first_sln, target_os, target_os_only,
   # We want to pass all non-solution revisions into the gclient sync call.
   solution_dirs = {sln['name'] for sln in solutions}
   gc_revisions = {
-      dirname: rev for dirname, rev in revisions.iteritems()
+      dirname: rev for dirname, rev in revisions.items()
       if dirname not in solution_dirs}
   # Gclient sometimes ignores "unmanaged": "False" in the gclient solution
   # if --revision <anything> is passed (for example, for subrepos).
@@ -903,7 +905,7 @@ def parse_revisions(revisions, root):
         if not normalized_root.endswith('.git'):
           normalized_root += '.git'
       elif parsed_root.scheme:
-        print 'WARNING: Unrecognized scheme %s, ignoring' % parsed_root.scheme
+        print('WARNING: Unrecognized scheme %s, ignoring' % parsed_root.scheme)
         continue
       else:
         # This is probably a local path.
@@ -992,10 +994,9 @@ def parse_args():
     with open(options.revision_mapping_file, 'r') as f:
       options.revision_mapping = json.load(f)
   except Exception as e:
-    print (
+    print(
         'WARNING: Caught execption while parsing revision_mapping*: %s'
-        % (str(e),)
-    )
+        % (str(e),))
 
   # Because we print CACHE_DIR out into a .gclient file, and then later run
   # eval() on it, backslashes need to be escaped, otherwise "E:\b\build" gets
@@ -1026,23 +1027,23 @@ def prepare(options, git_slns, active):
   first_sln = dir_names[0]
 
   # Split all the revision specifications into a nice dict.
-  print 'Revisions: %s' % options.revision
+  print('Revisions: %s' % options.revision)
   revisions = parse_revisions(options.revision, first_sln)
-  print 'Fetching Git checkout at %s@%s' % (first_sln, revisions[first_sln])
+  print('Fetching Git checkout at %s@%s' % (first_sln, revisions[first_sln]))
   return revisions, step_text
 
 
 def checkout(options, git_slns, specs, revisions, step_text):
-  print 'Using Python version: %s' % (sys.version,)
-  print 'Checking git version...'
+  print('Using Python version: %s' % (sys.version,))
+  print('Checking git version...')
   ver = git('version').strip()
-  print 'Using %s' % ver
+  print('Using %s' % ver)
 
   try:
     protocol = git('config', '--get', 'protocol.version')
-    print 'Using git protocol version %s' % protocol
+    print('Using git protocol version %s' % protocol)
   except SubprocessFailed as e:
-    print 'git protocol version is not specified.'
+    print('git protocol version is not specified.')
 
   first_sln = git_slns[0]['name']
   dir_names = [sln.get('name') for sln in git_slns if 'name' in sln]
@@ -1076,7 +1077,7 @@ def checkout(options, git_slns, specs, revisions, step_text):
           disable_syntax_validation=options.disable_syntax_validation)
       gclient_output = ensure_checkout(**checkout_parameters)
     except GclientSyncFailed:
-      print 'We failed gclient sync, lets delete the checkout and retry.'
+      print('We failed gclient sync, lets delete the checkout and retry.')
       ensure_no_checkout(dir_names, options.cleanup_dir)
       gclient_output = ensure_checkout(**checkout_parameters)
   except PatchFailed as e:
@@ -1126,14 +1127,14 @@ def checkout(options, git_slns, specs, revisions, step_text):
 
 
 def print_debug_info():
-  print "Debugging info:"
+  print("Debugging info:")
   debug_params = {
     'CURRENT_DIR': path.abspath(os.getcwd()),
     'THIS_DIR': THIS_DIR,
     'DEPOT_TOOLS_DIR': DEPOT_TOOLS_DIR,
   }
-  for k, v in sorted(debug_params.iteritems()):
-    print "%s: %r" % (k, v)
+  for k, v in sorted(debug_params.items()):
+    print("%s: %r" % (k, v))
 
 
 def main():
diff --git a/recipes/recipe_modules/bot_update/test_api.py b/recipes/recipe_modules/bot_update/test_api.py
index 7851d1746..0202a952b 100644
--- a/recipes/recipe_modules/bot_update/test_api.py
+++ b/recipes/recipe_modules/bot_update/test_api.py
@@ -20,12 +20,12 @@ class BotUpdateTestApi(recipe_test_api.RecipeTestApi):
 
     properties = {
         property_name: self.gen_revision(project_name)
-        for property_name, project_name in revision_mapping.iteritems()
+        for property_name, project_name in revision_mapping.items()
     }
     properties.update({
         '%s_cp' % property_name: ('refs/heads/master@{#%s}' %
                                   self.gen_commit_position(project_name))
-        for property_name, project_name in revision_mapping.iteritems()
+        for property_name, project_name in revision_mapping.items()
     })
 
     output.update({
diff --git a/recipes/recipe_modules/cipd/api.py b/recipes/recipe_modules/cipd/api.py
index eb5161197..3b9f1553e 100644
--- a/recipes/recipe_modules/cipd/api.py
+++ b/recipes/recipe_modules/cipd/api.py
@@ -36,7 +36,7 @@ def check_list_type(name, var, expect_inner):
 
 def check_dict_type(name, var, expect_key, expect_value):
   check_type(name, var, dict)
-  for key, value in var.iteritems():
+  for key, value in var.items():
     check_type('%s: key' % name, key, expect_key)
     check_type('%s[%s]' % (name, key), value, expect_value)
 
diff --git a/recipes/recipe_modules/gclient/api.py b/recipes/recipe_modules/gclient/api.py
index 6a8e31fba..9fb0e1962 100644
--- a/recipes/recipe_modules/gclient/api.py
+++ b/recipes/recipe_modules/gclient/api.py
@@ -133,7 +133,7 @@ class GclientApi(recipe_api.RecipeApi):
     rev_map = cfg.got_revision_mapping.as_jsonish()
     reverse_rev_map = cfg.got_revision_reverse_mapping.as_jsonish()
     combined_length = len(rev_map) + len(reverse_rev_map)
-    reverse_rev_map.update({v: k for k, v in rev_map.iteritems()})
+    reverse_rev_map.update({v: k for k, v in rev_map.items()})
 
     # Make sure we never have duplicate values in the old map.
     assert combined_length == len(reverse_rev_map)
@@ -194,7 +194,7 @@ class GclientApi(recipe_api.RecipeApi):
       result = self.m.step.active_result
       solutions = result.json.output['solutions']
       for propname, path in sorted(
-          self.got_revision_reverse_mapping(cfg).iteritems()):
+          self.got_revision_reverse_mapping(cfg).items()):
         # gclient json paths always end with a slash
         info = solutions.get(path + '/') or solutions.get(path)
         if info:
@@ -213,7 +213,7 @@ class GclientApi(recipe_api.RecipeApi):
     """
     cfg = gclient_config or self.c
 
-    for prop, custom_var in cfg.parent_got_revision_mapping.iteritems():
+    for prop, custom_var in cfg.parent_got_revision_mapping.items():
       val = str(self.m.properties.get(prop, ''))
       # TODO(infra): Fix coverage.
       if val:  # pragma: no cover
@@ -282,7 +282,7 @@ class GclientApi(recipe_api.RecipeApi):
             for cur_file in files:
               if cur_file.endswith('index.lock'):
                 path_to_file = os.path.join(path, cur_file)
-                print 'deleting %s' % path_to_file
+                print('deleting %s' % path_to_file)
                 os.remove(path_to_file)
       """,
       args=[self.m.path['start_dir']],
@@ -336,7 +336,7 @@ class GclientApi(recipe_api.RecipeApi):
       return rel_path
 
     # repo_path_map keys may be non-canonical.
-    for key, (rel_path, _) in cfg.repo_path_map.iteritems():
+    for key, (rel_path, _) in cfg.repo_path_map.items():
       if self._canonicalize_repo_url(key) == repo_url:
         return rel_path
 
diff --git a/recipes/recipe_modules/gclient/examples/full.expected/basic.json b/recipes/recipe_modules/gclient/examples/full.expected/basic.json
index 1de9d09fa..14239ec3d 100644
--- a/recipes/recipe_modules/gclient/examples/full.expected/basic.json
+++ b/recipes/recipe_modules/gclient/examples/full.expected/basic.json
@@ -197,7 +197,7 @@
     "cmd": [
       "python",
       "-u",
-      "\nimport os, sys\n\nbuild_path = sys.argv[1]\nif os.path.exists(build_path):\n  for (path, dir, files) in os.walk(build_path):\n    for cur_file in files:\n      if cur_file.endswith('index.lock'):\n        path_to_file = os.path.join(path, cur_file)\n        print 'deleting %s' % path_to_file\n        os.remove(path_to_file)\n",
+      "\nimport os, sys\n\nbuild_path = sys.argv[1]\nif os.path.exists(build_path):\n  for (path, dir, files) in os.walk(build_path):\n    for cur_file in files:\n      if cur_file.endswith('index.lock'):\n        path_to_file = os.path.join(path, cur_file)\n        print('deleting %s' % path_to_file)\n        os.remove(path_to_file)\n",
       "[START_DIR]"
     ],
     "infra_step": true,
@@ -212,7 +212,7 @@
       "@@@STEP_LOG_LINE@python.inline@    for cur_file in files:@@@",
       "@@@STEP_LOG_LINE@python.inline@      if cur_file.endswith('index.lock'):@@@",
       "@@@STEP_LOG_LINE@python.inline@        path_to_file = os.path.join(path, cur_file)@@@",
-      "@@@STEP_LOG_LINE@python.inline@        print 'deleting %s' % path_to_file@@@",
+      "@@@STEP_LOG_LINE@python.inline@        print('deleting %s' % path_to_file)@@@",
       "@@@STEP_LOG_LINE@python.inline@        os.remove(path_to_file)@@@",
       "@@@STEP_LOG_END@python.inline@@@"
     ]
diff --git a/recipes/recipe_modules/gclient/examples/full.expected/buildbot.json b/recipes/recipe_modules/gclient/examples/full.expected/buildbot.json
index 7493e628f..a6f7a066e 100644
--- a/recipes/recipe_modules/gclient/examples/full.expected/buildbot.json
+++ b/recipes/recipe_modules/gclient/examples/full.expected/buildbot.json
@@ -197,7 +197,7 @@
     "cmd": [
       "python",
       "-u",
-      "\nimport os, sys\n\nbuild_path = sys.argv[1]\nif os.path.exists(build_path):\n  for (path, dir, files) in os.walk(build_path):\n    for cur_file in files:\n      if cur_file.endswith('index.lock'):\n        path_to_file = os.path.join(path, cur_file)\n        print 'deleting %s' % path_to_file\n        os.remove(path_to_file)\n",
+      "\nimport os, sys\n\nbuild_path = sys.argv[1]\nif os.path.exists(build_path):\n  for (path, dir, files) in os.walk(build_path):\n    for cur_file in files:\n      if cur_file.endswith('index.lock'):\n        path_to_file = os.path.join(path, cur_file)\n        print('deleting %s' % path_to_file)\n        os.remove(path_to_file)\n",
       "[START_DIR]"
     ],
     "infra_step": true,
@@ -212,7 +212,7 @@
       "@@@STEP_LOG_LINE@python.inline@    for cur_file in files:@@@",
       "@@@STEP_LOG_LINE@python.inline@      if cur_file.endswith('index.lock'):@@@",
       "@@@STEP_LOG_LINE@python.inline@        path_to_file = os.path.join(path, cur_file)@@@",
-      "@@@STEP_LOG_LINE@python.inline@        print 'deleting %s' % path_to_file@@@",
+      "@@@STEP_LOG_LINE@python.inline@        print('deleting %s' % path_to_file)@@@",
       "@@@STEP_LOG_LINE@python.inline@        os.remove(path_to_file)@@@",
       "@@@STEP_LOG_END@python.inline@@@"
     ]
diff --git a/recipes/recipe_modules/gclient/examples/full.expected/revision.json b/recipes/recipe_modules/gclient/examples/full.expected/revision.json
index f4ec3f49d..9c7da1d53 100644
--- a/recipes/recipe_modules/gclient/examples/full.expected/revision.json
+++ b/recipes/recipe_modules/gclient/examples/full.expected/revision.json
@@ -199,7 +199,7 @@
     "cmd": [
       "python",
       "-u",
-      "\nimport os, sys\n\nbuild_path = sys.argv[1]\nif os.path.exists(build_path):\n  for (path, dir, files) in os.walk(build_path):\n    for cur_file in files:\n      if cur_file.endswith('index.lock'):\n        path_to_file = os.path.join(path, cur_file)\n        print 'deleting %s' % path_to_file\n        os.remove(path_to_file)\n",
+      "\nimport os, sys\n\nbuild_path = sys.argv[1]\nif os.path.exists(build_path):\n  for (path, dir, files) in os.walk(build_path):\n    for cur_file in files:\n      if cur_file.endswith('index.lock'):\n        path_to_file = os.path.join(path, cur_file)\n        print('deleting %s' % path_to_file)\n        os.remove(path_to_file)\n",
       "[START_DIR]"
     ],
     "infra_step": true,
@@ -214,7 +214,7 @@
       "@@@STEP_LOG_LINE@python.inline@    for cur_file in files:@@@",
       "@@@STEP_LOG_LINE@python.inline@      if cur_file.endswith('index.lock'):@@@",
       "@@@STEP_LOG_LINE@python.inline@        path_to_file = os.path.join(path, cur_file)@@@",
-      "@@@STEP_LOG_LINE@python.inline@        print 'deleting %s' % path_to_file@@@",
+      "@@@STEP_LOG_LINE@python.inline@        print('deleting %s' % path_to_file)@@@",
       "@@@STEP_LOG_LINE@python.inline@        os.remove(path_to_file)@@@",
       "@@@STEP_LOG_END@python.inline@@@"
     ]
diff --git a/recipes/recipe_modules/gclient/examples/full.expected/tryserver.json b/recipes/recipe_modules/gclient/examples/full.expected/tryserver.json
index 1de9d09fa..14239ec3d 100644
--- a/recipes/recipe_modules/gclient/examples/full.expected/tryserver.json
+++ b/recipes/recipe_modules/gclient/examples/full.expected/tryserver.json
@@ -197,7 +197,7 @@
     "cmd": [
       "python",
       "-u",
-      "\nimport os, sys\n\nbuild_path = sys.argv[1]\nif os.path.exists(build_path):\n  for (path, dir, files) in os.walk(build_path):\n    for cur_file in files:\n      if cur_file.endswith('index.lock'):\n        path_to_file = os.path.join(path, cur_file)\n        print 'deleting %s' % path_to_file\n        os.remove(path_to_file)\n",
+      "\nimport os, sys\n\nbuild_path = sys.argv[1]\nif os.path.exists(build_path):\n  for (path, dir, files) in os.walk(build_path):\n    for cur_file in files:\n      if cur_file.endswith('index.lock'):\n        path_to_file = os.path.join(path, cur_file)\n        print('deleting %s' % path_to_file)\n        os.remove(path_to_file)\n",
       "[START_DIR]"
     ],
     "infra_step": true,
@@ -212,7 +212,7 @@
       "@@@STEP_LOG_LINE@python.inline@    for cur_file in files:@@@",
       "@@@STEP_LOG_LINE@python.inline@      if cur_file.endswith('index.lock'):@@@",
       "@@@STEP_LOG_LINE@python.inline@        path_to_file = os.path.join(path, cur_file)@@@",
-      "@@@STEP_LOG_LINE@python.inline@        print 'deleting %s' % path_to_file@@@",
+      "@@@STEP_LOG_LINE@python.inline@        print('deleting %s' % path_to_file)@@@",
       "@@@STEP_LOG_LINE@python.inline@        os.remove(path_to_file)@@@",
       "@@@STEP_LOG_END@python.inline@@@"
     ]
diff --git a/recipes/recipe_modules/gerrit/api.py b/recipes/recipe_modules/gerrit/api.py
index c331a090c..94a0e0a3f 100644
--- a/recipes/recipe_modules/gerrit/api.py
+++ b/recipes/recipe_modules/gerrit/api.py
@@ -105,7 +105,7 @@ class GerritApi(recipe_api.RecipeApi):
         o_params=['ALL_REVISIONS', 'ALL_COMMITS'],
         limit=1)
     cl = cls[0] if len(cls) == 1 else {'revisions': {}}
-    for ri in cl['revisions'].itervalues():
+    for ri in cl['revisions'].values():
       # TODO(tandrii): add support for patchset=='current'.
       if str(ri['_number']) == str(patchset):
         return ri
diff --git a/recipes/recipe_modules/git/api.py b/recipes/recipe_modules/git/api.py
index 0be93f775..d26003fc1 100644
--- a/recipes/recipe_modules/git/api.py
+++ b/recipes/recipe_modules/git/api.py
@@ -18,7 +18,7 @@ class GitApi(recipe_api.RecipeApi):
     git_cmd = ['git']
 
     options = kwargs.pop('git_config_options', {})
-    for k, v in sorted(options.iteritems()):
+    for k, v in sorted(options.items()):
       git_cmd.extend(['-c', '%s=%s' % (k, v)])
     can_fail_build = kwargs.pop('can_fail_build', True)
     try:
@@ -59,7 +59,7 @@ class GitApi(recipe_api.RecipeApi):
     """
     if previous_result:
       assert isinstance(previous_result, dict)
-      assert all(isinstance(v, long) for v in previous_result.itervalues())
+      assert all(isinstance(v, long) for v in previous_result.values())
       assert 'size' in previous_result
       assert 'size-pack' in previous_result
 
@@ -78,14 +78,14 @@ class GitApi(recipe_api.RecipeApi):
         result[name] = long(value.strip())
 
       def results_to_text(results):
-        return ['  %s: %s' % (k, v) for k, v in results.iteritems()]
+        return ['  %s: %s' % (k, v) for k, v in results.items()]
 
       step_result.presentation.logs['result'] = results_to_text(result)
 
       if previous_result:
         delta = {
             key: value - previous_result[key]
-            for key, value in result.iteritems()
+            for key, value in result.items()
             if key in previous_result}
         step_result.presentation.logs['delta'] = (
             ['before:'] + results_to_text(previous_result) +
diff --git a/recipes/recipe_modules/gitiles/resources/gerrit_client.py b/recipes/recipe_modules/gitiles/resources/gerrit_client.py
index c38fc301d..64b66e885 100755
--- a/recipes/recipe_modules/gitiles/resources/gerrit_client.py
+++ b/recipes/recipe_modules/gitiles/resources/gerrit_client.py
@@ -167,12 +167,12 @@ def main(arguments):
         em = tf._extract_member
         def _extract_member(tarinfo, targetpath):
           if not os.path.abspath(targetpath).startswith(args.extract_to):
-            print 'Skipping %s' % (tarinfo.name,)
+            print('Skipping %s' % (tarinfo.name,))
             ret['skipped']['filecount'] += 1
             ret['skipped']['bytes'] += tarinfo.size
             ret['skipped']['names'].append(tarinfo.name)
             return
-          print 'Extracting %s' % (tarinfo.name,)
+          print('Extracting %s' % (tarinfo.name,))
           ret['extracted']['filecount'] += 1
           ret['extracted']['bytes'] += tarinfo.size
           return em(tarinfo, targetpath)
diff --git a/recipes/recipe_modules/gsutil/api.py b/recipes/recipe_modules/gsutil/api.py
index bcae5deb2..c222290a8 100644
--- a/recipes/recipe_modules/gsutil/api.py
+++ b/recipes/recipe_modules/gsutil/api.py
@@ -160,7 +160,7 @@ class GSUtilApi(recipe_api.RecipeApi):
   def _generate_metadata_args(self, metadata):
     result = []
     if metadata:
-      for k, v in sorted(metadata.iteritems(), key=lambda (k, _): k):
+      for k, v in sorted(metadata.items(), key=lambda (k, _): k):
         field = self._get_metadata_field(k)
         param = (field) if v is None else ('%s:%s' % (field, v))
         result += ['-h', param]
diff --git a/recipes/recipe_modules/tryserver/api.py b/recipes/recipe_modules/tryserver/api.py
index 16bffc200..2da8ada17 100644
--- a/recipes/recipe_modules/tryserver/api.py
+++ b/recipes/recipe_modules/tryserver/api.py
@@ -89,7 +89,7 @@ class TryserverApi(recipe_api.RecipeApi):
       self._gerrit_change_target_ref = (
           'refs/heads/' + self._gerrit_change_target_ref)
 
-    for rev in res['revisions'].itervalues():
+    for rev in res['revisions'].values():
       if int(rev['_number']) == self.gerrit_change.patchset:
         self._gerrit_change_fetch_ref = rev['ref']
         break
diff --git a/roll_dep.py b/roll_dep.py
index 63fc3ff96..5e4a08e34 100755
--- a/roll_dep.py
+++ b/roll_dep.py
@@ -171,7 +171,7 @@ def finalize(commit_msg, current_dir, rolls):
 
   # Pull the dependency to the right revision. This is surprising to users
   # otherwise.
-  for _head, roll_to, full_dir in sorted(rolls.itervalues()):
+  for _head, roll_to, full_dir in sorted(rolls.values()):
     check_call(['git', 'checkout', '--quiet', roll_to], cwd=full_dir)
 
 
@@ -249,7 +249,7 @@ def main():
 
     logs = []
     setdep_args = []
-    for dependency, (head, roll_to, full_dir) in sorted(rolls.iteritems()):
+    for dependency, (head, roll_to, full_dir) in sorted(rolls.items()):
       log = generate_commit_message(
           full_dir, dependency, head, roll_to, args.no_log, args.log_limit)
       logs.append(log)
diff --git a/split_cl.py b/split_cl.py
index d54a09a9a..f4fc74cc3 100644
--- a/split_cl.py
+++ b/split_cl.py
@@ -229,7 +229,7 @@ def SplitCl(description_file, comment_file, changelist, cmd_upload, dry_run,
         return 0
 
     for cl_index, (directory, files) in \
-        enumerate(files_split_by_owners.iteritems(), 1):
+        enumerate(files_split_by_owners.items(), 1):
       # Use '/' as a path separator in the branch name and the CL description
       # and comment.
       directory = directory.replace(os.path.sep, '/')
diff --git a/testing_support/auto_stub.py b/testing_support/auto_stub.py
index b266692e9..a47a8b244 100644
--- a/testing_support/auto_stub.py
+++ b/testing_support/auto_stub.py
@@ -26,8 +26,8 @@ class AutoStubMixIn(object):
   def tearDown(self):
     """Restore all the mocked members."""
     if self._saved:
-      for obj, items in self._saved.iteritems():
-        for member, previous_value in items.iteritems():
+      for obj, items in self._saved.items():
+        for member, previous_value in items.items():
           setattr(obj, member, previous_value)
 
 
@@ -57,7 +57,7 @@ class SimpleMock(object):
     """Registers the name of the caller function."""
     caller_name = kwargs.pop('caller_name', None) or inspect.stack()[1][3]
     str_args = ', '.join(repr(arg) for arg in args)
-    str_kwargs = ', '.join('%s=%r' % (k, v) for k, v in kwargs.iteritems())
+    str_kwargs = ', '.join('%s=%r' % (k, v) for k, v in kwargs.items())
     self.calls.append('%s(%s)' % (
         caller_name, ', '.join(filter(None, [str_args, str_kwargs]))))
 
diff --git a/testing_support/fake_repos.py b/testing_support/fake_repos.py
index e6b43a6c3..a4c665f6d 100755
--- a/testing_support/fake_repos.py
+++ b/testing_support/fake_repos.py
@@ -467,7 +467,7 @@ deps = {
 pre_deps_hooks = [
   {
     'action': ['python', '-c',
-               'print "pre-deps hook"; open(\\'src/git_pre_deps_hooked\\', \\'w\\').write(\\'git_pre_deps_hooked\\')'],
+               'print("pre-deps hook"); open(\\'src/git_pre_deps_hooked\\', \\'w\\').write(\\'git_pre_deps_hooked\\')'],
   }
 ]
 """ % {
@@ -489,7 +489,7 @@ deps = {
 pre_deps_hooks = [
   {
     'action': ['python', '-c',
-               'print "pre-deps hook"; open(\\'src/git_pre_deps_hooked\\', \\'w\\').write(\\'git_pre_deps_hooked\\')'],
+               'print("pre-deps hook"); open(\\'src/git_pre_deps_hooked\\', \\'w\\').write(\\'git_pre_deps_hooked\\')'],
   },
   {
     'action': ['python', '-c', 'import sys; sys.exit(1)'],
diff --git a/tests/presubmit_unittest.py b/tests/presubmit_unittest.py
index af7acd3cf..98da9975f 100755
--- a/tests/presubmit_unittest.py
+++ b/tests/presubmit_unittest.py
@@ -1922,7 +1922,7 @@ the current line as well!
         "#!/bin/python\n"
         "# Copyright (c) 2037 Nobody.\n"
         "# All Rights Reserved.\n"
-        "print 'foo'\n"
+        "print('foo')\n"
     )
     license_text = (
         r".*? Copyright \(c\) 2037 Nobody." "\n"
@@ -1935,7 +1935,7 @@ the current line as well!
         "#!/bin/python\n"
         "# Copyright (c) 2037 Nobody.\n"
         "# All Rights Reserved.\n"
-        "print 'foo'\n"
+        "print('foo')\n"
     )
     license_text = (
         r".*? Copyright \(c\) 0007 Nobody." "\n"
@@ -1949,7 +1949,7 @@ the current line as well!
         "#!/bin/python\n"
         "# Copyright (c) 2037 Nobody.\n"
         "# All Rights Reserved.\n"
-        "print 'foo'\n"
+        "print('foo')\n"
     )
     license_text = (
         r".*? Copyright \(c\) 0007 Nobody." "\n"
diff --git a/watchlists.py b/watchlists.py
index 096eb10e7..f8d6a131f 100755
--- a/watchlists.py
+++ b/watchlists.py
@@ -94,7 +94,7 @@ class Watchlists(object):
     # Compile the regular expressions ahead of time to avoid creating them
     # on-the-fly multiple times per file.
     self._path_regexps = {}
-    for name, rule in defns.iteritems():
+    for name, rule in defns.items():
       filepath = rule.get('filepath')
       if not filepath:
         continue
@@ -117,7 +117,7 @@ class Watchlists(object):
     watchers = set()  # A set, to avoid duplicates
     for path in paths:
       path = path.replace(os.sep, '/')
-      for name, rule in self._path_regexps.iteritems():
+      for name, rule in self._path_regexps.items():
         if name not in self._watchlists:
           continue
         if rule.search(path):
diff --git a/win_toolchain/package_from_installed.py b/win_toolchain/package_from_installed.py
index ec37c850b..fd495c126 100644
--- a/win_toolchain/package_from_installed.py
+++ b/win_toolchain/package_from_installed.py
@@ -343,24 +343,24 @@ def GenerateSetEnvCmd(target_dir):
   with open(set_env_prefix + '.cmd', 'w') as f:
     f.write('@echo off\n'
             ':: Generated by win_toolchain\\package_from_installed.py.\n')
-    for var, dirs in env.iteritems():
+    for var, dirs in env.items():
       f.write('set %s=%s\n' % (var, BatDirs(dirs)))
     f.write('if "%1"=="/x64" goto x64\n')
     f.write('if "%1"=="/arm64" goto arm64\n')
 
-    for var, dirs in env_x86.iteritems():
+    for var, dirs in env_x86.items():
       f.write('set %s=%s%s\n' % (
           var, BatDirs(dirs), ';%PATH%' if var == 'PATH' else ''))
     f.write('goto :EOF\n')
 
     f.write(':x64\n')
-    for var, dirs in env_x64.iteritems():
+    for var, dirs in env_x64.items():
       f.write('set %s=%s%s\n' % (
           var, BatDirs(dirs), ';%PATH%' if var == 'PATH' else ''))
     f.write('goto :EOF\n')
 
     f.write(':arm64\n')
-    for var, dirs in env_arm64.iteritems():
+    for var, dirs in env_arm64.items():
       f.write('set %s=%s%s\n' % (
           var, BatDirs(dirs), ';%PATH%' if var == 'PATH' else ''))
     f.write('goto :EOF\n')