diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -1436,11 +1436,14 @@ def commit(ui, repo, *pats, **opts):
             try:
                 if opts.get('secret'):
                     ui.setconfig('phases', 'new-commit', 'secret')
+                    # Propagate to subrepos
+                    repo.baseui.setconfig('phases', 'new-commit', 'secret')
 
                 return repo.commit(message, opts.get('user'), opts.get('date'),
                                    match, editor=e, extra=extra)
             finally:
                 ui.setconfig('phases', 'new-commit', oldcommitphase)
+                repo.baseui.setconfig('phases', 'new-commit', oldcommitphase)
 
 
         node = cmdutil.commit(ui, repo, commitfunc, pats, opts)
diff --git a/tests/test-subrepo.t b/tests/test-subrepo.t
--- a/tests/test-subrepo.t
+++ b/tests/test-subrepo.t
@@ -1294,3 +1294,18 @@ configuration
   15: secret
 
   $ cd ..
+
+
+Test that comit --secret works on both repo and subrepo (issue4182)
+
+  $ cd main
+  $ echo secret >> b
+  $ echo secret >> s/b
+  $ hg commit --secret --subrepo -m "secret"
+  committing subrepository s
+  $ hg phase -r .
+  6: secret
+  $ cd s
+  $ hg phase -r .
+  6: secret
+  $ cd ../../