diff --git a/dlls/ntoskrnl.exe/ntoskrnl.c b/dlls/ntoskrnl.exe/ntoskrnl.c
index bc127882877..06320d03cc9 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.c
+++ b/dlls/ntoskrnl.exe/ntoskrnl.c
@@ -681,6 +681,15 @@ void WINAPI IoStartTimer(PDEVICE_OBJECT DeviceObject)
 }
 
 
+/***********************************************************************
+ *           IoStopTimer   (NTOSKRNL.EXE.@)
+ */
+void WINAPI IoStopTimer(PDEVICE_OBJECT DeviceObject)
+{
+    FIXME( "stub: %p\n", DeviceObject );
+}
+
+
 /***********************************************************************
  *           IoAllocateIrp  (NTOSKRNL.EXE.@)
  */
diff --git a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
index acc740fc719..efa69fe4537 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
+++ b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
@@ -463,7 +463,7 @@
 @ stub IoStartPacket
 @ stdcall IoStartTimer(ptr)
 @ stub IoStatisticsLock
-@ stub IoStopTimer
+@ stdcall IoStopTimer(ptr)
 @ stub IoSynchronousInvalidateDeviceRelations
 @ stub IoSynchronousPageWrite
 @ stub IoThreadToProcess