diff --git a/app/scodoc/sco_groups.py b/app/scodoc/sco_groups.py
index 18c53e73..5277ea5a 100644
--- a/app/scodoc/sco_groups.py
+++ b/app/scodoc/sco_groups.py
@@ -1499,7 +1499,7 @@ def _sortgroups(groups):
     # Tri: place 'all' en tête, puis groupe par partition / nom de groupe
     R = [g for g in groups if g["partition_name"] is None]
     o = [g for g in groups if g["partition_name"] != None]
-    o.sort(key=lambda x: (x["numero"], x["group_name"]))
+    o.sort(key=lambda x: (x["numero"] or 0, x["group_name"]))
 
     return R + o