diff --git a/git_cl_hooks.py b/git_cl_hooks.py
index 81d48cea0..70c4f3201 100644
--- a/git_cl_hooks.py
+++ b/git_cl_hooks.py
@@ -11,6 +11,7 @@ import breakpad
 
 import presubmit_support
 import scm
+import watchlists
 
 def Backquote(cmd, cwd=None):
   """Like running `cmd` in a shell script."""
@@ -52,6 +53,14 @@ def RunHooks(hook_name, upstream_branch):
   # Create our options based on the command-line args and the current checkout.
   options = ChangeOptions(commit=commit, upstream_branch=upstream_branch)
 
+  # Apply watchlists on upload.
+  if not commit:
+    watchlist = watchlists.Watchlists(options.change.RepositoryRoot())
+    files = [f.LocalPath() for f in options.change.AffectedFiles()]
+    watchers = watchlist.GetWatchersForPaths(files)
+    Backquote(['git', 'config', '--add',
+               'rietveld.extra_cc', ','.join(watchers)])
+
   # Run the presubmit checks.
   if presubmit_support.DoPresubmitChecks(options.change,
                                          options.commit,