diff --git a/roles/matrix/templates/homeserver.yaml.j2 b/roles/matrix/templates/homeserver.yaml.j2
index dec61af1b842615c58b34bfcad7bedfaa219107e..294fb649dcda4731b693770ef42777a7e95647fa 100644
--- a/roles/matrix/templates/homeserver.yaml.j2
+++ b/roles/matrix/templates/homeserver.yaml.j2
@@ -715,6 +715,7 @@ caches:
   #
   per_cache_factors:
     #get_users_who_share_room_with_user: 2.0
+    get_users_in_room: 2.0
 
   # Controls how long an entry can be in a cache without having been
   # accessed before being evicted. Defaults to None, which means