diff --git a/django/contrib/admin/helpers.py b/django/contrib/admin/helpers.py
index 613e63e449..7a60943d46 100644
--- a/django/contrib/admin/helpers.py
+++ b/django/contrib/admin/helpers.py
@@ -23,7 +23,10 @@ class AdminForm(object):
         if self.form._meta.fields is not None:
             name = self.form._meta.fields[0]
             return forms.BoundField(self.form, self.form.fields[name], name)
-        return iter(self.form).next()
+        try:
+            return iter(self.form).next()
+        except StopIteration:
+            return None
 
     def _media(self):
         media = self.form.media