diff --git a/MdeModulePkg/Universal/BdsDxe/BdsEntry.c b/MdeModulePkg/Universal/BdsDxe/BdsEntry.c
index c86cd7a576..aacc4a6479 100644
--- a/MdeModulePkg/Universal/BdsDxe/BdsEntry.c
+++ b/MdeModulePkg/Universal/BdsDxe/BdsEntry.c
@@ -654,7 +654,7 @@ BdsEntry (
   Status = gBS->LocateProtocol (&gEdkiiVariableLockProtocolGuid, NULL, (VOID **) &VariableLock);
   DEBUG ((EFI_D_INFO, "[BdsDxe] Locate Variable Lock protocol - %r\n", Status));
   if (!EFI_ERROR (Status)) {
-    for (Index = 0; Index < sizeof (mReadOnlyVariables) / sizeof (mReadOnlyVariables[0]); Index++) {
+    for (Index = 0; Index < ARRAY_SIZE (mReadOnlyVariables); Index++) {
       Status = VariableLock->RequestToLock (VariableLock, mReadOnlyVariables[Index], &gEfiGlobalVariableGuid);
       ASSERT_EFI_ERROR (Status);
     }