diff --git a/django/utils/itercompat.py b/django/utils/itercompat.py
index ff814bfd7b1..0de1b6cbe28 100644
--- a/django/utils/itercompat.py
+++ b/django/utils/itercompat.py
@@ -34,7 +34,7 @@ def groupby(iterable, keyfunc=None):
         keyfunc = lambda x:x
     iterable = iter(iterable)
     l = [iterable.next()]
-    lastkey = keyfunc(l)
+    lastkey = keyfunc(l[0])
     for item in iterable:
         key = keyfunc(item)
         if key != lastkey: