diff --git a/Code/Tools/AssetProcessor/native/tests/assetmanager/TestEventSignal.h b/Code/Tools/AssetProcessor/native/tests/assetmanager/TestEventSignal.h
index 5251be5b3f..c76d4e522e 100644
--- a/Code/Tools/AssetProcessor/native/tests/assetmanager/TestEventSignal.h
+++ b/Code/Tools/AssetProcessor/native/tests/assetmanager/TestEventSignal.h
@@ -9,6 +9,7 @@
 #pragma once
 
 #include <AzCore/std/parallel/binary_semaphore.h>
+#include <AzCore/std/parallel/atomic.h>
 
 namespace UnitTests
 {