diff --git a/core/src/main/scala/org/apache/spark/ui/ToolTips.scala b/core/src/main/scala/org/apache/spark/ui/ToolTips.scala
index 063e2a1f8b18e..e2d25e36365fa 100644
--- a/core/src/main/scala/org/apache/spark/ui/ToolTips.scala
+++ b/core/src/main/scala/org/apache/spark/ui/ToolTips.scala
@@ -35,6 +35,10 @@ private[spark] object ToolTips {
 
   val OUTPUT = "Bytes and records written to Hadoop."
 
+  val STORAGE_MEMORY =
+    "Memory used / total available memory for storage of data " +
+      "like RDD partitions cached in memory. "
+
   val SHUFFLE_WRITE =
     "Bytes and records written to disk in order to be read by a shuffle in a future stage."
 
diff --git a/core/src/main/scala/org/apache/spark/ui/exec/ExecutorsPage.scala b/core/src/main/scala/org/apache/spark/ui/exec/ExecutorsPage.scala
index b247e4cdc3bd4..01cddda4c62cd 100644
--- a/core/src/main/scala/org/apache/spark/ui/exec/ExecutorsPage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/exec/ExecutorsPage.scala
@@ -67,7 +67,7 @@ private[ui] class ExecutorsPage(
           <th>Executor ID</th>
           <th>Address</th>
           <th>RDD Blocks</th>
-          <th>Memory Used</th>
+          <th><span data-toggle="tooltip" title={ToolTips.STORAGE_MEMORY}>Storage Memory</span></th>
           <th>Disk Used</th>
           <th>Active Tasks</th>
           <th>Failed Tasks</th>