diff --git a/dlls/user32/edit.c b/dlls/user32/edit.c
index 9bbfa2727b2..28d93b98b83 100644
--- a/dlls/user32/edit.c
+++ b/dlls/user32/edit.c
@@ -3633,7 +3633,7 @@ static LRESULT EDIT_WM_LButtonDown(EDITSTATE *es, DWORD keys, INT x, INT y)
 static LRESULT EDIT_WM_LButtonUp(EDITSTATE *es)
 {
 	if (es->bCaptureState) {
-		KillTimer(es->hwndSelf, 0);
+		NtUserKillTimer(es->hwndSelf, 0);
 		if (GetCapture() == es->hwndSelf) ReleaseCapture();
 	}
 	es->bCaptureState = FALSE;
diff --git a/dlls/user32/message.c b/dlls/user32/message.c
index eee4759513a..7fe9df68508 100644
--- a/dlls/user32/message.c
+++ b/dlls/user32/message.c
@@ -4417,25 +4417,6 @@ UINT_PTR WINAPI SetTimer( HWND hwnd, UINT_PTR id, UINT timeout, TIMERPROC proc )
 }
 
 
-/***********************************************************************
- *		KillTimer (USER32.@)
- */
-BOOL WINAPI KillTimer( HWND hwnd, UINT_PTR id )
-{
-    BOOL ret;
-
-    SERVER_START_REQ( kill_win_timer )
-    {
-        req->win = wine_server_user_handle( hwnd );
-        req->msg = WM_TIMER;
-        req->id  = id;
-        ret = !wine_server_call_err( req );
-    }
-    SERVER_END_REQ;
-    return ret;
-}
-
-
 /***********************************************************************
  *		KillSystemTimer (USER32.@)
  */
diff --git a/dlls/user32/user32.spec b/dlls/user32/user32.spec
index c5ea5e6c4c0..7c27d9400db 100644
--- a/dlls/user32/user32.spec
+++ b/dlls/user32/user32.spec
@@ -484,7 +484,7 @@
 @ stdcall IsWindowVisible(long)
 @ stdcall IsZoomed(long)
 @ stdcall KillSystemTimer(long long)
-@ stdcall KillTimer(long long)
+@ stdcall KillTimer(long long) NtUserKillTimer
 @ stdcall LoadAcceleratorsA(long str)
 @ stdcall LoadAcceleratorsW(long wstr)
 @ stdcall LoadBitmapA(long str)
diff --git a/dlls/win32u/message.c b/dlls/win32u/message.c
index 5fb238566f3..d70984dbe2b 100644
--- a/dlls/win32u/message.c
+++ b/dlls/win32u/message.c
@@ -192,6 +192,24 @@ UINT_PTR WINAPI NtUserSetSystemTimer( HWND hwnd, UINT_PTR id, UINT timeout, TIME
     return ret;
 }
 
+/***********************************************************************
+ *           NtUserKillTimer (win32u.@)
+ */
+BOOL WINAPI NtUserKillTimer( HWND hwnd, UINT_PTR id )
+{
+    BOOL ret;
+
+    SERVER_START_REQ( kill_win_timer )
+    {
+        req->win = wine_server_user_handle( hwnd );
+        req->msg = WM_TIMER;
+        req->id  = id;
+        ret = !wine_server_call_err( req );
+    }
+    SERVER_END_REQ;
+    return ret;
+}
+
 /* see SendMessageW */
 LRESULT send_message( HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam )
 {
diff --git a/dlls/win32u/syscall.c b/dlls/win32u/syscall.c
index 5dbf6f43ac6..2be2cfce3bf 100644
--- a/dlls/win32u/syscall.c
+++ b/dlls/win32u/syscall.c
@@ -142,6 +142,7 @@ static void * const syscalls[] =
     NtUserGetWindowRgnEx,
     NtUserInitializeClientPfnArrays,
     NtUserInternalGetWindowText,
+    NtUserKillTimer,
     NtUserNotifyWinEvent,
     NtUserOpenDesktop,
     NtUserOpenInputDesktop,
diff --git a/dlls/win32u/win32u.spec b/dlls/win32u/win32u.spec
index 9c6103b84f8..96d8d4833b0 100644
--- a/dlls/win32u/win32u.spec
+++ b/dlls/win32u/win32u.spec
@@ -1059,7 +1059,7 @@
 @ stub NtUserIsTouchWindow
 @ stub NtUserIsWindowBroadcastingDpiToChildren
 @ stub NtUserIsWindowGDIScaledDpiMessageEnabled
-@ stub NtUserKillTimer
+@ stdcall -syscall NtUserKillTimer(long long)
 @ stub NtUserLayoutCompleted
 @ stub NtUserLinkDpiCursor
 @ stub NtUserLoadKeyboardLayoutEx
diff --git a/dlls/wow64win/syscall.h b/dlls/wow64win/syscall.h
index 4b181ecba89..7b6bbb5eda6 100644
--- a/dlls/wow64win/syscall.h
+++ b/dlls/wow64win/syscall.h
@@ -127,6 +127,7 @@
     SYSCALL_ENTRY( NtUserGetWindowRgnEx ) \
     SYSCALL_ENTRY( NtUserInitializeClientPfnArrays ) \
     SYSCALL_ENTRY( NtUserInternalGetWindowText ) \
+    SYSCALL_ENTRY( NtUserKillTimer ) \
     SYSCALL_ENTRY( NtUserNotifyWinEvent ) \
     SYSCALL_ENTRY( NtUserOpenDesktop ) \
     SYSCALL_ENTRY( NtUserOpenInputDesktop ) \
diff --git a/dlls/wow64win/user.c b/dlls/wow64win/user.c
index 2af7f9a3115..1a43b4793fb 100644
--- a/dlls/wow64win/user.c
+++ b/dlls/wow64win/user.c
@@ -554,6 +554,14 @@ NTSTATUS WINAPI wow64_NtUserSetTimer( UINT *args )
     return NtUserSetTimer( hwnd, id, timeout, proc, tolerance );
 }
 
+NTSTATUS WINAPI wow64_NtUserKillTimer( UINT *args )
+{
+    HWND hwnd = get_handle( &args );
+    UINT_PTR id = get_ulong( &args );
+
+    return NtUserKillTimer( hwnd, id );
+}
+
 NTSTATUS WINAPI wow64_NtUserCopyAcceleratorTable( UINT *args )
 {
     HACCEL src = get_handle( &args );
diff --git a/include/ntuser.h b/include/ntuser.h
index afa4d0d561f..3352a63e1ea 100644
--- a/include/ntuser.h
+++ b/include/ntuser.h
@@ -365,6 +365,7 @@ NTSTATUS WINAPI NtUserInitializeClientPfnArrays( const struct user_client_procs
                                                  const void *client_workers, HINSTANCE user_module );
 INT     WINAPI NtUserInternalGetWindowText( HWND hwnd, WCHAR *text, INT count );
 BOOL    WINAPI NtUserIsClipboardFormatAvailable( UINT format );
+BOOL    WINAPI NtUserKillTimer( HWND hwnd, UINT_PTR id );
 UINT    WINAPI NtUserMapVirtualKeyEx( UINT code, UINT type, HKL layout );
 BOOL    WINAPI NtUserMessageCall( HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam,
                                   ULONG_PTR result_info, DWORD type, BOOL ansi );