new file mode 100644
--- /dev/null
+++ b/hghooks/mozhghooks/prevent_bookmarks.py
@@ -0,0 +1,19 @@
+# This software may be used and distributed according to the terms of the
+# GNU General Public License version 2 or any later version.
+
+"""Hook that prevents bookmarks from being set.
+
+It may not prevent bookmark setting via all scenarios. The main aim is to
+prevent bookmark pushing via the wire protocol.
+"""
+
+def hook(ui, repo, hooktype, namespace, key, old, new, source=None, **kwargs):
+    if source in ('pull', 'strip'):
+        return 0
+
+    if namespace != 'bookmarks':
+        return 0
+
+    ui.write('bookmarks are disabled on this repository; '
+             'refusing to accept modification to "%s"\n' % key)
+    return 1

new file mode 100644
--- /dev/null
+++ b/hghooks/tests/test-prevent-bookmarks.t
@@ -0,0 +1,42 @@
+  $ hg init server
+  $ cd server
+  $ cat >> .hg/hgrc << EOF
+  > [hooks]
+  > prepushkey.prevent_bookmarks = python:mozhghooks.prevent_bookmarks.hook
+  > EOF
+  $ cd ..
+
+  $ hg clone server client
+  updating to branch default
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ cd client
+  $ touch foo
+  $ hg -q commit -A -m initial
+  $ hg push
+  pushing to $TESTTMP/server
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+
+Pushing a bookmark is not allowed
+
+  $ hg book book1
+  $ hg push -B book1
+  pushing to $TESTTMP/server
+  searching for changes
+  no changes found
+  bookmarks are disabled on this repository; refusing to accept modification to "book1"
+  pushkey-abort: prepushkey.prevent_bookmarks hook failed
+  abort: exporting bookmark book1 failed!
+  [255]
+
+Pulling a bookmark on the server is allowed
+
+  $ cd ../server
+  $ hg pull ../client
+  pulling from ../client
+  searching for changes
+  no changes found
+  adding remote bookmark book1