diff --git a/MdePkg/Include/Guid/EventGroup.h b/MdePkg/Include/Guid/EventGroup.h
index 64bfd4bab9..b0dc002a18 100644
--- a/MdePkg/Include/Guid/EventGroup.h
+++ b/MdePkg/Include/Guid/EventGroup.h
@@ -34,6 +34,11 @@ extern EFI_GUID  gEfiEventMemoryMapChangeGuid;
 
 extern EFI_GUID  gEfiEventReadyToBootGuid;
 
+#define EFI_EVENT_GROUP_AFTER_READY_TO_BOOT \
+  { 0x3a2a00ad, 0x98b9, 0x4cdf, { 0xa4, 0x78, 0x70, 0x27, 0x77, 0xf1, 0xc1, 0xb } }
+
+extern EFI_GUID  gEfiEventAfterReadyToBootGuid;
+
 #define EFI_EVENT_GROUP_DXE_DISPATCH_GUID \
   { 0x7081e22f, 0xcac6, 0x4053, { 0x94, 0x68, 0x67, 0x57, 0x82, 0xcf, 0x88, 0xe5 }}
 
diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
index 3d08f20d15..a7ad520419 100644
--- a/MdePkg/MdePkg.dec
+++ b/MdePkg/MdePkg.dec
@@ -413,6 +413,9 @@
   ## Include/Guid/EventGroup.h
   gEfiEventReadyToBootGuid       = { 0x7CE88FB3, 0x4BD7, 0x4679, { 0x87, 0xA8, 0xA8, 0xD8, 0xDE, 0xE5, 0x0D, 0x2B }}
 
+  ## Include/Guid/EventGroup.h
+  gEfiEventAfterReadyToBootGuid  = { 0x3a2a00ad, 0x98b9, 0x4cdf, { 0xa4, 0x78, 0x70, 0x27, 0x77, 0xf1, 0xc1, 0x0b }}
+
   ## Include/Guid/EventGroup.h
   gEfiEventMemoryMapChangeGuid   = { 0x78BEE926, 0x692F, 0x48FD, { 0x9E, 0xDB, 0x01, 0x42, 0x2E, 0xF0, 0xD7, 0xAB }}