diff --git a/sql/core/src/main/scala/org/apache/spark/sql/sources/ddl.scala b/sql/core/src/main/scala/org/apache/spark/sql/sources/ddl.scala
index 8a66ac31f2dfb..364bacec83b98 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/sources/ddl.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/sources/ddl.scala
@@ -110,7 +110,8 @@ private[sql] case class CreateTableUsing(
 /**
  * Builds a map in which keys are case insensitive
  */
-protected class CaseInsensitiveMap(map: Map[String, String]) extends Map[String, String] {
+protected class CaseInsensitiveMap(map: Map[String, String]) extends Map[String, String] 
+  with Serializable {
 
   val baseMap = map.map(kv => kv.copy(_1 = kv._1.toLowerCase))