--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -2457,6 +2457,8 @@ def serve(ui, repo, **opts):
     for o in optlist.split():
         if opts[o]:
             parentui.setconfig("web", o, str(opts[o]))
+            if repo.ui != parentui:
+                repo.ui.setconfig("web", o, str(opts[o]))
 
     if repo is None and not ui.config("web", "webdir_conf"):
         raise hg.RepoError(_("There is no Mercurial repository here"