diff --git a/dlls/hal/hal.spec b/dlls/hal/hal.spec
index d44ffb96fa9..d8db011914f 100644
--- a/dlls/hal/hal.spec
+++ b/dlls/hal/hal.spec
@@ -71,7 +71,7 @@
 @ stdcall -arch=i386 KeAcquireSpinLock(ptr ptr)
 @ stub KeFlushWriteBuffer
 @ stdcall -arch=arm,arm64,i386 KeGetCurrentIrql()
-@ stub KeLowerIrql
+@ stdcall -arch=x86_64 KeLowerIrql(long) ntoskrnl.exe.KeLowerIrql
 @ stdcall -ret64 KeQueryPerformanceCounter(ptr)
 @ stub KeRaiseIrql
 @ stub KeRaiseIrqlToDpcLevel
diff --git a/dlls/ntoskrnl.exe/ntoskrnl.c b/dlls/ntoskrnl.exe/ntoskrnl.c
index 556b683e8f4..f3495796e23 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.c
+++ b/dlls/ntoskrnl.exe/ntoskrnl.c
@@ -4462,6 +4462,11 @@ void WINAPI KfRaiseIrql(KIRQL new, KIRQL *old)
     FIXME("new %u old %p: stub.\n", new, old);
 }
 
+void WINAPI KeLowerIrql(KIRQL new)
+{
+    FIXME("new %u: stub.\n", new);
+}
+
 #endif
 
 /*****************************************************
diff --git a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
index 84f4a3feec3..8ae4bc1f5a9 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
+++ b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
@@ -589,6 +589,7 @@
 @ stub KeIsExecutingDpc
 @ stdcall KeLeaveCriticalRegion()
 @ stub KeLoaderBlock
+@ stdcall -arch=x86_64 KeLowerIrql(long)
 @ stub KeNumberProcessors
 @ stub KeProfileInterrupt
 @ stub KeProfileInterruptWithSource