diff --git a/MdePkg/Include/IndustryStandard/Acpi10.h b/MdePkg/Include/IndustryStandard/Acpi10.h
index c05a6051b4..dbd61a2e40 100644
--- a/MdePkg/Include/IndustryStandard/Acpi10.h
+++ b/MdePkg/Include/IndustryStandard/Acpi10.h
@@ -23,6 +23,7 @@ typedef struct {
   UINT32  Length;
 } EFI_ACPI_COMMON_HEADER;
 
+#pragma pack(1)
 ///
 /// Common ACPI description table header.  This structure prefaces most ACPI tables.
 ///
@@ -37,6 +38,7 @@ typedef struct {
   UINT32  CreatorId;
   UINT32  CreatorRevision;
 } EFI_ACPI_DESCRIPTION_HEADER;
+#pragma pack()
 
 //
 // Define for Desriptor
diff --git a/MdePkg/Include/IndustryStandard/Acpi20.h b/MdePkg/Include/IndustryStandard/Acpi20.h
index b67ee54440..4476bf9f22 100644
--- a/MdePkg/Include/IndustryStandard/Acpi20.h
+++ b/MdePkg/Include/IndustryStandard/Acpi20.h
@@ -99,6 +99,10 @@ typedef struct {
 ///
 #define EFI_ACPI_2_0_EXTENDED_SYSTEM_DESCRIPTION_TABLE_REVISION 0x01
 
+//           
+// Ensure proper structure formats
+//           
+#pragma pack(1)
 ///
 /// Fixed ACPI Description Table Structure (FADT)
 ///
@@ -156,6 +160,7 @@ typedef struct {
   EFI_ACPI_2_0_GENERIC_ADDRESS_STRUCTURE  XGpe0Blk;
   EFI_ACPI_2_0_GENERIC_ADDRESS_STRUCTURE  XGpe1Blk;
 } EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE;
+#pragma pack()
 
 ///
 /// FADT Version (as defined in ACPI 2.0 spec.)
diff --git a/MdePkg/Include/IndustryStandard/Acpi30.h b/MdePkg/Include/IndustryStandard/Acpi30.h
index d07cce5807..207f060bee 100644
--- a/MdePkg/Include/IndustryStandard/Acpi30.h
+++ b/MdePkg/Include/IndustryStandard/Acpi30.h
@@ -108,6 +108,10 @@ typedef struct {
 ///
 #define EFI_ACPI_3_0_EXTENDED_SYSTEM_DESCRIPTION_TABLE_REVISION 0x01
 
+//           
+// Ensure proper structure formats
+//           
+#pragma pack(1)
 ///
 /// Fixed ACPI Description Table Structure (FADT)
 ///
@@ -165,6 +169,7 @@ typedef struct {
   EFI_ACPI_3_0_GENERIC_ADDRESS_STRUCTURE  XGpe0Blk;
   EFI_ACPI_3_0_GENERIC_ADDRESS_STRUCTURE  XGpe1Blk;
 } EFI_ACPI_3_0_FIXED_ACPI_DESCRIPTION_TABLE;
+#pragma pack()
 
 ///
 /// FADT Version (as defined in ACPI 3.0 spec.)