diff --git a/python/pyspark/sql/dataframe.py b/python/pyspark/sql/dataframe.py
index 9168ad20dbbcc..da75193aba30d 100644
--- a/python/pyspark/sql/dataframe.py
+++ b/python/pyspark/sql/dataframe.py
@@ -26,6 +26,8 @@
 else:
     from itertools import imap as map
 
+import warnings
+
 from pyspark import copy_func, since
 from pyspark.rdd import RDD, _load_from_socket, ignore_unicode_prefix
 from pyspark.serializers import BatchedSerializer, PickleSerializer, UTF8Deserializer