diff --git a/docs/running-on-yarn.md b/docs/running-on-yarn.md
index 68ab127bcf..2b93eef6c2 100644
--- a/docs/running-on-yarn.md
+++ b/docs/running-on-yarn.md
@@ -104,6 +104,13 @@ Most of the configs are the same for Spark on YARN as for other deployment modes
     Comma-separated list of files to be placed in the working directory of each executor.
   </td>
 </tr>
+<tr>
+ <td><code>spark.executor.instances</code></td>
+  <td>2</td>
+  <td>
+    The number of executors. Note that this property is incompatible with <code>spark.dynamicAllocation.enabled</code>.
+  </td>
+</tr>
 <tr>
  <td><code>spark.yarn.executor.memoryOverhead</code></td>
   <td>executorMemory * 0.07, with minimum of 384 </td>