diff --git a/app/views/absences.py b/app/views/absences.py
index 0f782ad0d..c65a2d497 100644
--- a/app/views/absences.py
+++ b/app/views/absences.py
@@ -715,7 +715,10 @@ def _gen_form_saisie_groupe(
     jn = sco_abs.day_names()
     for d in odates:
         idx_jour = d.weekday()
-        noms_jours.append(jn[idx_jour])
+        if 0 <= idx_jour < len(jn):
+            noms_jours.append(jn[idx_jour])
+        else:
+            noms_jours.append("???")  # jour non travaillé
     for jour in noms_jours:
         H.append(
             f"""<th colspan="2" width="100px" style="padding-left: 5px; padding-right: 5px;">