diff --git a/python/pyspark/streaming/dstream.py b/python/pyspark/streaming/dstream.py
index 8a9e2dab7fb07..ffcf70cc854ab 100644
--- a/python/pyspark/streaming/dstream.py
+++ b/python/pyspark/streaming/dstream.py
@@ -354,6 +354,15 @@ def groupByKeyAndWindow(self, windowDuration, slideDuration, numPartitions=None)
 
     def reduceByKeyAndWindow(self, func, invFunc,
                              windowDuration, slideDuration, numPartitions=None):
+
+        duration = self._jdstream.dstream().slideDuration().milliseconds()
+        if int(windowDuration * 1000) % duration != 0:
+            raise ValueError("windowDuration must be multiple of the slide duration (%d ms)"
+                             % duration)
+        if int(slideDuration * 1000) % duration != 0:
+            raise ValueError("slideDuration must be multiple of the slide duration (%d ms)"
+                             % duration)
+
         reduced = self.reduceByKey(func)
 
         def reduceFunc(a, b, t):
diff --git a/python/pyspark/streaming/tests.py b/python/pyspark/streaming/tests.py
index 06fcc29850504..843d6ee04ca33 100644
--- a/python/pyspark/streaming/tests.py
+++ b/python/pyspark/streaming/tests.py
@@ -292,6 +292,12 @@ def func(dstream):
                     [('a', [2, 3, 4])], [('a', [3, 4])], [('a', [4])]]
         self._test_func(input, func, expected)
 
+    def test_reduce_by_invalid_window(self):
+        input1 = [range(3), range(5), range(1), range(6)]
+        d1 = self.ssc.queueStream(input1)
+        self.assertRaises(ValueError, lambda: d1.reduceByKeyAndWindow(None, None, 0.1, 0.1))
+        self.assertRaises(ValueError, lambda: d1.reduceByKeyAndWindow(None, None, 1, 0.1))
+
     def update_state_by_key(self):
 
         def updater(it):
diff --git a/streaming/src/main/scala/org/apache/spark/streaming/api/python/PythonDStream.scala b/streaming/src/main/scala/org/apache/spark/streaming/api/python/PythonDStream.scala
index 66cf0c968478c..47c3974b61699 100644
--- a/streaming/src/main/scala/org/apache/spark/streaming/api/python/PythonDStream.scala
+++ b/streaming/src/main/scala/org/apache/spark/streaming/api/python/PythonDStream.scala
@@ -92,7 +92,8 @@ private[spark] object PythonDStream {
  * If the result RDD is PythonRDD, then it will cache it as an template for future use,
  * this can reduce the Python callbacks.
  */
-private[spark] class PythonTransformedDStream (parent: DStream[_], pfunc: PythonRDDFunction,
+private[spark]
+class PythonTransformedDStream (parent: DStream[_], pfunc: PythonRDDFunction,
                                 var reuse: Boolean = false)
   extends PythonDStream(parent) {
 
@@ -180,16 +181,6 @@ class PythonReducedWindowedDStream(parent: DStream[Array[Byte]],
                                    _slideDuration: Duration
                                    ) extends PythonStateDStream(parent, preduceFunc) {
 
-  assert(_windowDuration.isMultipleOf(parent.slideDuration),
-    "The window duration of ReducedWindowedDStream (" + _windowDuration + ") " +
-      "must be multiple of the slide duration of parent DStream (" + parent.slideDuration + ")"
-  )
-
-  assert(_slideDuration.isMultipleOf(parent.slideDuration),
-    "The slide duration of ReducedWindowedDStream (" + _slideDuration + ") " +
-      "must be multiple of the slide duration of parent DStream (" + parent.slideDuration + ")"
-  )
-
   val invReduceFunc = new RDDFunction(pinvReduceFunc)
 
   def windowDuration: Duration = _windowDuration