diff --git a/StandaloneMmPkg/Core/StandaloneMmCore.h b/StandaloneMmPkg/Core/StandaloneMmCore.h
index da123c530c..ba7266249d 100644
--- a/StandaloneMmPkg/Core/StandaloneMmCore.h
+++ b/StandaloneMmPkg/Core/StandaloneMmCore.h
@@ -9,8 +9,7 @@
 
 **/
 
-#ifndef _MM_CORE_H_
-#define _MM_CORE_H_
+#pragma once
 
 #include <PiMm.h>
 #include <StandaloneMm.h>
@@ -1025,5 +1024,3 @@ VOID
 MmFreeShadowedFvs (
   VOID
   );
-
-#endif
diff --git a/StandaloneMmPkg/Core/StandaloneMmCorePrivateData.h b/StandaloneMmPkg/Core/StandaloneMmCorePrivateData.h
index 03b0261ef0..04dfdbe158 100644
--- a/StandaloneMmPkg/Core/StandaloneMmCorePrivateData.h
+++ b/StandaloneMmPkg/Core/StandaloneMmCorePrivateData.h
@@ -8,8 +8,7 @@
 
 **/
 
-#ifndef _STANDALONE_MM_CORE_PRIVATE_DATA_H_
-#define _STANDALONE_MM_CORE_PRIVATE_DATA_H_
+#pragma once
 
 //
 // Page management
@@ -54,5 +53,3 @@ typedef struct {
 } FREE_POOL_HEADER;
 
 extern LIST_ENTRY  mMmPoolLists[MAX_POOL_INDEX];
-
-#endif
diff --git a/StandaloneMmPkg/Drivers/MmCommunicationDxe/MmCommunicationDxe.h b/StandaloneMmPkg/Drivers/MmCommunicationDxe/MmCommunicationDxe.h
index 80d2bfa2b3..58cd5d9ff5 100644
--- a/StandaloneMmPkg/Drivers/MmCommunicationDxe/MmCommunicationDxe.h
+++ b/StandaloneMmPkg/Drivers/MmCommunicationDxe/MmCommunicationDxe.h
@@ -5,8 +5,7 @@
 
 **/
 
-#ifndef MM_COMMUNICATION_DXE_H_
-#define MM_COMMUNICATION_DXE_H_
+#pragma once
 
 #include <PiDxe.h>
 
@@ -138,5 +137,3 @@ MmVirtualAddressChangeEvent (
   IN EFI_EVENT  Event,
   IN VOID       *Context
   );
-
-#endif
diff --git a/StandaloneMmPkg/Drivers/MmCommunicationNotifyDxe/MmCommunicationNotifyDxe.h b/StandaloneMmPkg/Drivers/MmCommunicationNotifyDxe/MmCommunicationNotifyDxe.h
index 83391dcabd..a45dad88e6 100644
--- a/StandaloneMmPkg/Drivers/MmCommunicationNotifyDxe/MmCommunicationNotifyDxe.h
+++ b/StandaloneMmPkg/Drivers/MmCommunicationNotifyDxe/MmCommunicationNotifyDxe.h
@@ -5,8 +5,7 @@
 
 **/
 
-#ifndef MM_COMMUNICATION_NOTIFY_DXE_H_
-#define MM_COMMUNICATION_NOTIFY_DXE_H_
+#pragma once
 
 #include <PiDxe.h>
 
@@ -152,5 +151,3 @@ MmEndOfDxeEventNotify (
   IN EFI_EVENT  Event,
   IN VOID       *Context
   );
-
-#endif
diff --git a/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.h b/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.h
index 430e7c578b..b82363e26f 100644
--- a/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.h
+++ b/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.h
@@ -6,8 +6,7 @@
 
 **/
 
-#ifndef STANDALONE_MM_IPL_PEI_H_
-#define STANDALONE_MM_IPL_PEI_H_
+#pragma once
 
 #include <StandaloneMm.h>
 #include <Guid/MmCommBuffer.h>
@@ -176,5 +175,3 @@ CreateMmHobHandoffInfoTable (
   IN EFI_HOB_HANDOFF_INFO_TABLE  *Hob,
   IN VOID                        *HobEnd
   );
-
-#endif
diff --git a/StandaloneMmPkg/Include/Guid/MmFvDispatch.h b/StandaloneMmPkg/Include/Guid/MmFvDispatch.h
index 6ddc89bb87..8b773f452c 100644
--- a/StandaloneMmPkg/Include/Guid/MmFvDispatch.h
+++ b/StandaloneMmPkg/Include/Guid/MmFvDispatch.h
@@ -8,8 +8,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
 
-#ifndef __MM_FV_DISPATCH_H__
-#define __MM_FV_DISPATCH_H__
+#pragma once
 
 #define MM_FV_DISPATCH_GUID \
   { 0xb65694cc, 0x9e3, 0x4c3b, { 0xb5, 0xcd, 0x5, 0xf4, 0x4d, 0x3c, 0xdb, 0xff }}
@@ -29,5 +28,3 @@ typedef struct {
   EFI_MM_COMMUNICATE_FV_DISPATCH_DATA    Data;
 } EFI_MM_COMMUNICATE_FV_DISPATCH;
 #pragma pack()
-
-#endif
diff --git a/StandaloneMmPkg/Include/Guid/MmStatusCodeUseSerial.h b/StandaloneMmPkg/Include/Guid/MmStatusCodeUseSerial.h
index 1477b9bda2..bea15c1419 100644
--- a/StandaloneMmPkg/Include/Guid/MmStatusCodeUseSerial.h
+++ b/StandaloneMmPkg/Include/Guid/MmStatusCodeUseSerial.h
@@ -8,8 +8,7 @@
 
 **/
 
-#ifndef MM_STATUS_CODE_USE_SERIAL_H_
-#define MM_STATUS_CODE_USE_SERIAL_H_
+#pragma once
 
 ///
 /// The GUID of the StatusCodeUseSerial GUIDed HOB.
@@ -31,5 +30,3 @@ typedef struct {
 } MM_STATUS_CODE_USE_SERIAL;
 
 extern EFI_GUID  gMmStatusCodeUseSerialHobGuid;
-
-#endif
diff --git a/StandaloneMmPkg/Include/Guid/MmramMemoryReserve.h b/StandaloneMmPkg/Include/Guid/MmramMemoryReserve.h
index 1159d3adcf..4dc89636b9 100644
--- a/StandaloneMmPkg/Include/Guid/MmramMemoryReserve.h
+++ b/StandaloneMmPkg/Include/Guid/MmramMemoryReserve.h
@@ -18,8 +18,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
 
-#ifndef _EFI_MM_PEI_MMRAM_MEMORY_RESERVE_H_
-#define _EFI_MM_PEI_MMRAM_MEMORY_RESERVE_H_
+#pragma once
 
 #define EFI_MM_PEI_MMRAM_MEMORY_RESERVE \
   { \
@@ -51,5 +50,3 @@ typedef struct {
 } EFI_MMRAM_HOB_DESCRIPTOR_BLOCK;
 
 extern EFI_GUID  gEfiMmPeiSmramMemoryReserveGuid;
-
-#endif
diff --git a/StandaloneMmPkg/Include/Guid/MpInformation.h b/StandaloneMmPkg/Include/Guid/MpInformation.h
index dbf88d12de..32f8c91d6a 100644
--- a/StandaloneMmPkg/Include/Guid/MpInformation.h
+++ b/StandaloneMmPkg/Include/Guid/MpInformation.h
@@ -10,8 +10,7 @@
 
 **/
 
-#ifndef _MP_INFORMATION_H_
-#define _MP_INFORMATION_H_
+#pragma once
 
 #include <Protocol/MpService.h>
 #include <PiPei.h>
@@ -31,5 +30,3 @@ typedef struct {
 #pragma pack()
 
 extern EFI_GUID  gMpInformationHobGuid;
-
-#endif
diff --git a/StandaloneMmPkg/Include/Library/MmPlatformHobProducerLib.h b/StandaloneMmPkg/Include/Library/MmPlatformHobProducerLib.h
index ec01152e3b..5c4ef329fa 100644
--- a/StandaloneMmPkg/Include/Library/MmPlatformHobProducerLib.h
+++ b/StandaloneMmPkg/Include/Library/MmPlatformHobProducerLib.h
@@ -10,8 +10,7 @@
 
 **/
 
-#ifndef MM_PLATFORM_HOB_PRODUCER_LIB_H_
-#define MM_PLATFORM_HOB_PRODUCER_LIB_H_
+#pragma once
 
 /**
   Create the platform specific HOBs needed by the Standalone MM environment.
@@ -51,5 +50,3 @@ CreateMmPlatformHob (
   IN      VOID   *Buffer,
   IN  OUT UINTN  *BufferSize
   );
-
-#endif
diff --git a/StandaloneMmPkg/Include/Library/StandaloneMmMemLib.h b/StandaloneMmPkg/Include/Library/StandaloneMmMemLib.h
index 9c48995fd7..383a1fc500 100644
--- a/StandaloneMmPkg/Include/Library/StandaloneMmMemLib.h
+++ b/StandaloneMmPkg/Include/Library/StandaloneMmMemLib.h
@@ -12,8 +12,7 @@
 
 **/
 
-#ifndef _MM_MEM_LIB_H_
-#define _MM_MEM_LIB_H_
+#pragma once
 
 /**
   This function check if the buffer is valid per processor architecture and not overlap with MMRAM.
@@ -130,5 +129,3 @@ MmSetMem (
   IN UINTN  Length,
   IN UINT8  Value
   );
-
-#endif
diff --git a/StandaloneMmPkg/Include/Ppi/MmCoreFvLocationPpi.h b/StandaloneMmPkg/Include/Ppi/MmCoreFvLocationPpi.h
index 5769ac4212..8c6e0709b6 100644
--- a/StandaloneMmPkg/Include/Ppi/MmCoreFvLocationPpi.h
+++ b/StandaloneMmPkg/Include/Ppi/MmCoreFvLocationPpi.h
@@ -9,8 +9,7 @@
 
 **/
 
-#ifndef MM_CORE_FV_LOCATION_PPI_H_
-#define MM_CORE_FV_LOCATION_PPI_H_
+#pragma once
 
 #pragma pack(1)
 
@@ -30,5 +29,3 @@ typedef struct {
 extern EFI_GUID  gMmCoreFvLocationPpiGuid;
 
 #pragma pack()
-
-#endif
diff --git a/StandaloneMmPkg/Include/StandaloneMm.h b/StandaloneMmPkg/Include/StandaloneMm.h
index 743ab517f9..ba7573d713 100644
--- a/StandaloneMmPkg/Include/StandaloneMm.h
+++ b/StandaloneMmPkg/Include/StandaloneMm.h
@@ -8,8 +8,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
 
-#ifndef _STANDALONE_MM_H_
-#define _STANDALONE_MM_H_
+#pragma once
 
 #include <PiMm.h>
 
@@ -31,5 +30,3 @@ VOID
 // Will remove it once all the code references are removed.
 //
 typedef MM_FOUNDATION_ENTRY_POINT STANDALONE_MM_FOUNDATION_ENTRY_POINT;
-
-#endif
diff --git a/StandaloneMmPkg/Library/StandaloneMmMemLib/StandaloneMmMemLibInternal.h b/StandaloneMmPkg/Library/StandaloneMmMemLib/StandaloneMmMemLibInternal.h
index bb3701a3a0..1f58f9bc6f 100644
--- a/StandaloneMmPkg/Library/StandaloneMmMemLib/StandaloneMmMemLibInternal.h
+++ b/StandaloneMmPkg/Library/StandaloneMmMemLib/StandaloneMmMemLibInternal.h
@@ -6,8 +6,7 @@
 
 **/
 
-#ifndef STANDALONE_MM_MEM_LIB_INTERNAL_H_
-#define STANDALONE_MM_MEM_LIB_INTERNAL_H_
+#pragma once
 
 #include <PiMm.h>
 
@@ -56,5 +55,3 @@ MmMemLibIsValidNonMmramRange (
   IN EFI_PHYSICAL_ADDRESS  Buffer,
   IN UINT64                Length
   );
-
-#endif