diff --git a/docker/api/client.py b/docker/api/client.py
index 3f701de2..10729739 100644
--- a/docker/api/client.py
+++ b/docker/api/client.py
@@ -231,7 +231,7 @@ class APIClient(
             for k, v in six.iteritems(data):
                 if v is not None:
                     data2[k] = v
-        else:
+        elif data is not None:
             data2 = data
 
         if 'headers' not in kwargs: