diff --git a/django/utils/datastructures.py b/django/utils/datastructures.py
index 41b43b286cb00..ce5218deb3a9f 100644
--- a/django/utils/datastructures.py
+++ b/django/utils/datastructures.py
@@ -347,6 +347,7 @@ def setlistdefault(self, key, default_list=None):
             if default_list is None:
                 default_list = []
             self.setlist(key, default_list)
+            return default_list
         return self.getlist(key)
 
     def appendlist(self, key, value):