Index: django/db/models/query.py
===================================================================
--- django/db/models/query.py	(revision 5122)
+++ django/db/models/query.py	(working copy)
@@ -760,7 +763,7 @@
     """
 
     # If we've got a max_depth set and we've exceeded that depth, bail now.
-    if max_depth and cur_depth > max_depth:
+    if max_depth and cur_depth >= max_depth:
         return None
 
     qn = backend.quote_name