diff --git a/git_cl.py b/git_cl.py
index 3540382b0..22c158532 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -881,10 +881,10 @@ def ParseIssueNumberArgument(arg):
 
   if arg.isdigit():
     return _ParsedIssueNumberArgument(issue=int(arg))
-  if not arg.startswith('http'):
-    return fail_result
 
   url = gclient_utils.UpgradeToHttps(arg)
+  if not url.startswith('http'):
+    return fail_result
   for gerrit_url, short_url in _KNOWN_GERRIT_TO_SHORT_URLS.items():
     if url.startswith(short_url):
       url = gerrit_url + url[len(short_url):]
@@ -895,6 +895,11 @@ def ParseIssueNumberArgument(arg):
   except ValueError:
     return fail_result
 
+  # If "https://" was automatically added, fail if `arg` looks unlikely to be a
+  # URL.
+  if not arg.startswith('http') and '.' not in parsed_url.netloc:
+    return fail_result
+
   # Gerrit's new UI is https://domain/c/project/+/<issue_number>[/[patchset]]
   # But old GWT UI is https://domain/#/c/project/+/<issue_number>[/[patchset]]
   # Short urls like https://domain/<issue_number> can be used, but don't allow
diff --git a/tests/git_cl_test.py b/tests/git_cl_test.py
index a88c5e3a2..7be4ebc3c 100755
--- a/tests/git_cl_test.py
+++ b/tests/git_cl_test.py
@@ -476,6 +476,11 @@ class TestParseIssueURL(unittest.TestCase):
     self._test('https://crrev.com/c/2151934', 2151934, None,
                'chromium-review.googlesource.com')
 
+  def test_missing_scheme(self):
+    self._test('codereview.source.com/123', 123, None, 'codereview.source.com')
+    self._test('crrev.com/c/2151934', 2151934, None,
+               'chromium-review.googlesource.com')
+
 
 class GitCookiesCheckerTest(unittest.TestCase):
   def setUp(self):