diff --git a/mllib/src/main/scala/org/apache/spark/ml/tree/treeModels.scala b/mllib/src/main/scala/org/apache/spark/ml/tree/treeModels.scala
index 1929f9d02156e..4c643d9c6ce4b 100644
--- a/mllib/src/main/scala/org/apache/spark/ml/tree/treeModels.scala
+++ b/mllib/src/main/scala/org/apache/spark/ml/tree/treeModels.scala
@@ -17,6 +17,7 @@
 
 package org.apache.spark.ml.tree
 
+import org.apache.spark.mllib.linalg.{Vectors, Vector}
 
 /**
  * Abstraction for Decision Tree models.
@@ -70,6 +71,10 @@ private[ml] trait TreeEnsembleModel {
   /** Weights for each tree, zippable with [[trees]] */
   def treeWeights: Array[Double]
 
+  /** Weights used by the python wrappers. */
+  // Note: An array cannot be returned directly due to serialization problems.
+  def pyTreeWeights: Vector = Vectors.dense(treeWeights)
+
   /** Summary of the model */
   override def toString: String = {
     // Implementing classes should generally override this method to be more descriptive.
diff --git a/python/pyspark/ml/regression.py b/python/pyspark/ml/regression.py
index 2142b2a7bd966..40017fc39c08f 100644
--- a/python/pyspark/ml/regression.py
+++ b/python/pyspark/ml/regression.py
@@ -265,7 +265,8 @@ class TreeEnsembleModels(JavaModel):
 
     @property
     def treeWeights(self):
-        return list(self._call_java("treeWeights"))
+        """Return the weights for each tree"""
+        return list(self._call_java("pyTreeWeights"))
 
     def __repr__(self):
         return self._call_java("toString")