diff --git a/MdePkg/Include/AArch64/ProcessorBind.h b/MdePkg/Include/AArch64/ProcessorBind.h
index f09b15a558..c5fe874b1b 100644
--- a/MdePkg/Include/AArch64/ProcessorBind.h
+++ b/MdePkg/Include/AArch64/ProcessorBind.h
@@ -111,7 +111,9 @@ typedef INT64   INTN;
 //
 #define EFIAPI
 
-#if defined(__GNUC__)
+// When compiling with Clang, we still use GNU as for the assembler, so we still
+// need to define the GCC_ASM* macros.
+#if defined(__GNUC__) || defined(__clang__)
   ///
   /// For GNU assembly code, .global or .globl can declare global symbols.
   /// Define this macro to unify the usage.
diff --git a/MdePkg/Include/Arm/ProcessorBind.h b/MdePkg/Include/Arm/ProcessorBind.h
index cc763b396b..c2482c2f50 100644
--- a/MdePkg/Include/Arm/ProcessorBind.h
+++ b/MdePkg/Include/Arm/ProcessorBind.h
@@ -110,7 +110,9 @@ typedef INT32   INTN;
 //
 #define EFIAPI    
 
-#if defined(__GNUC__)
+// When compiling with Clang, we still use GNU as for the assembler, so we still
+// need to define the GCC_ASM* macros.
+#if defined(__GNUC__) || defined(__clang__)
   ///
   /// For GNU assembly code, .global or .globl can declare global symbols.
   /// Define this macro to unify the usage.