diff --git a/reactos/ntoskrnl/ps/w32call.c b/reactos/ntoskrnl/ps/w32call.c
index 37a634bedb3..0bbda42d6fc 100644
--- a/reactos/ntoskrnl/ps/w32call.c
+++ b/reactos/ntoskrnl/ps/w32call.c
@@ -292,7 +292,8 @@ NtW32Call (IN ULONG RoutineIndex,
   memcpy((char*)NewStack + StackSize - sizeof(KTRAP_FRAME) - sizeof(FX_SAVE_AREA),
          Thread->Tcb.TrapFrame, sizeof(KTRAP_FRAME) - (4 * sizeof(DWORD)));
   NewFrame = (PKTRAP_FRAME)((char*)NewStack + StackSize - sizeof(KTRAP_FRAME) - sizeof(FX_SAVE_AREA));
-  NewFrame->Esp -= (ArgumentLength + (4 * sizeof(ULONG)));
+  /* We need the stack pointer to remain 4-byte aligned */
+  NewFrame->Esp -= (((ArgumentLength + 3) & (~ 0x3)) + (4 * sizeof(ULONG)));
   NewFrame->Eip = (ULONG)LdrpGetSystemDllCallbackDispatcher();
   UserEsp = (PULONG)NewFrame->Esp;
   UserEsp[0] = 0;     /* Return address. */