diff --git a/toolz/itertoolz.py b/toolz/itertoolz.py
index 941b9a9f..577b1f19 100644
--- a/toolz/itertoolz.py
+++ b/toolz/itertoolz.py
@@ -884,7 +884,7 @@ def join(leftkey, leftseq, rightkey, rightseq,
                 yield (left_default, item)
 
     if right_default != no_default:
-        for key, matches in d.items():
+        for key, matches in iteritems(d):
             if key not in seen_keys:
                 for match in matches:
                     yield (match, right_default)