diff --git a/mercurial/hgweb/hgweb_mod.py b/mercurial/hgweb/hgweb_mod.py
--- a/mercurial/hgweb/hgweb_mod.py
+++ b/mercurial/hgweb/hgweb_mod.py
@@ -9,6 +9,7 @@
 from __future__ import absolute_import
 
 import contextlib
+import gc
 import os
 
 from .common import (
@@ -305,8 +306,19 @@
         with self._obtainrepo() as repo:
             profile = repo.ui.configbool('profiling', 'enabled')
             with profiling.profile(repo.ui, enabled=profile):
-                for r in self._runwsgi(req, res, repo):
-                    yield r
+                try:
+                    for r in self._runwsgi(req, res, repo):
+                        yield r
+                finally:
+                    # There are known cycles in localrepository that prevent
+                    # those objects (and tons of held references) from being
+                    # collected through normal refcounting. We mitigate those
+                    # leaks by performing an explicit GC on every request.
+                    # TODO remove this once leaks are fixed.
+                    # TODO only run this on requests that create localrepository
+                    # instances instead of every request.
+                    gc.collect()
+
 
     def _runwsgi(self, req, res, repo):
         rctx = requestcontext(self, repo, req, res)