diff --git a/ArmPkg/Drivers/ArmGic/ArmGicCommonDxe.c b/ArmPkg/Drivers/ArmGic/ArmGicCommonDxe.c
index a9ccef5e1c..be77b8361c 100644
--- a/ArmPkg/Drivers/ArmGic/ArmGicCommonDxe.c
+++ b/ArmPkg/Drivers/ArmGic/ArmGicCommonDxe.c
@@ -62,7 +62,7 @@ RegisterInterruptSource (
   IN HARDWARE_INTERRUPT_HANDLER         Handler
   )
 {
-  if (Source > mGicNumInterrupts) {
+  if (Source >= mGicNumInterrupts) {
     ASSERT(FALSE);
     return EFI_UNSUPPORTED;
   }
diff --git a/ArmPkg/Drivers/ArmGic/GicV2/ArmGicV2Dxe.c b/ArmPkg/Drivers/ArmGic/GicV2/ArmGicV2Dxe.c
index e649ac1bc6..036eb5cd6b 100644
--- a/ArmPkg/Drivers/ArmGic/GicV2/ArmGicV2Dxe.c
+++ b/ArmPkg/Drivers/ArmGic/GicV2/ArmGicV2Dxe.c
@@ -50,7 +50,7 @@ GicV2EnableInterruptSource (
   IN HARDWARE_INTERRUPT_SOURCE          Source
   )
 {
-  if (Source > mGicNumInterrupts) {
+  if (Source >= mGicNumInterrupts) {
     ASSERT(FALSE);
     return EFI_UNSUPPORTED;
   }
@@ -77,7 +77,7 @@ GicV2DisableInterruptSource (
   IN HARDWARE_INTERRUPT_SOURCE          Source
   )
 {
-  if (Source > mGicNumInterrupts) {
+  if (Source >= mGicNumInterrupts) {
     ASSERT(FALSE);
     return EFI_UNSUPPORTED;
   }
@@ -106,7 +106,7 @@ GicV2GetInterruptSourceState (
   IN BOOLEAN                            *InterruptState
   )
 {
-  if (Source > mGicNumInterrupts) {
+  if (Source >= mGicNumInterrupts) {
     ASSERT(FALSE);
     return EFI_UNSUPPORTED;
   }
@@ -134,7 +134,7 @@ GicV2EndOfInterrupt (
   IN HARDWARE_INTERRUPT_SOURCE          Source
   )
 {
-  if (Source > mGicNumInterrupts) {
+  if (Source >= mGicNumInterrupts) {
     ASSERT(FALSE);
     return EFI_UNSUPPORTED;
   }
diff --git a/ArmPkg/Drivers/ArmGic/GicV3/ArmGicV3Dxe.c b/ArmPkg/Drivers/ArmGic/GicV3/ArmGicV3Dxe.c
index 4afa3d5a09..50fa56262e 100644
--- a/ArmPkg/Drivers/ArmGic/GicV3/ArmGicV3Dxe.c
+++ b/ArmPkg/Drivers/ArmGic/GicV3/ArmGicV3Dxe.c
@@ -40,7 +40,7 @@ GicV3EnableInterruptSource (
   IN HARDWARE_INTERRUPT_SOURCE          Source
   )
 {
-  if (Source > mGicNumInterrupts) {
+  if (Source >= mGicNumInterrupts) {
     ASSERT(FALSE);
     return EFI_UNSUPPORTED;
   }
@@ -67,7 +67,7 @@ GicV3DisableInterruptSource (
   IN HARDWARE_INTERRUPT_SOURCE          Source
   )
 {
-  if (Source > mGicNumInterrupts) {
+  if (Source >= mGicNumInterrupts) {
     ASSERT(FALSE);
     return EFI_UNSUPPORTED;
   }
@@ -96,7 +96,7 @@ GicV3GetInterruptSourceState (
   IN BOOLEAN                            *InterruptState
   )
 {
-  if (Source > mGicNumInterrupts) {
+  if (Source >= mGicNumInterrupts) {
     ASSERT(FALSE);
     return EFI_UNSUPPORTED;
   }
@@ -124,7 +124,7 @@ GicV3EndOfInterrupt (
   IN HARDWARE_INTERRUPT_SOURCE          Source
   )
 {
-  if (Source > mGicNumInterrupts) {
+  if (Source >= mGicNumInterrupts) {
     ASSERT(FALSE);
     return EFI_UNSUPPORTED;
   }