diff --git a/mafiasi/settings.py b/mafiasi/settings.py
index 12248dd..dbed542 100644
--- a/mafiasi/settings.py
+++ b/mafiasi/settings.py
@@ -317,7 +317,7 @@
 BITPOLL_URL = env.str("MAFIASI_BITPOLL_URL", "https://bitpoll.mafiasi.de")
 WHITEBOARD_URL = "https://spacedeck.mafiasi.de"
 KANBOARD_URL = "https://kanboard.mafiasi.de"
-MATTERMOST_URL = "https://mattermost.mafiasi.de"
+MATTERMOST_URL = env.str("MAFIASI_MATTERMOST_URL", "https://mattermost.mafiasi.de")
 MATRIX_URL = "https://matrix.mafiasi.de"
 MENSA_URL = "https://mensa.mafiasi.de"
 MODULKOMPASS_URL = "https://modulkompass.mafiasi.de"