diff --git a/MdePkg/Include/Uefi/UefiBaseType.h b/MdePkg/Include/Uefi/UefiBaseType.h
index fb0ac22dbb..d4f4edc8ae 100644
--- a/MdePkg/Include/Uefi/UefiBaseType.h
+++ b/MdePkg/Include/Uefi/UefiBaseType.h
@@ -183,11 +183,6 @@ typedef union {
 ///
 #define RFC_3066_ENTRY_SIZE             (42 + 1)
 
-///
-/// The size of a 3 character ISO639 language code.
-///
-#define ISO_639_2_ENTRY_SIZE            3
-
 ///
 /// PE32+ Machine type for IA32 UEFI images
 ///