diff --git a/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c b/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c
index 29ce212825..16618a8f57 100644
--- a/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c
+++ b/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c
@@ -40,7 +40,9 @@ CONST UINT8 PciHostIrqs[] = {
 //
 // Array Size macro
 //
+#ifndef ARRAY_SIZE
 #define ARRAY_SIZE(array) (sizeof (array) / sizeof (array[0]))
+#endif
 
 //
 // Type definitions