diff --git a/dlls/user32/caret.c b/dlls/user32/caret.c
index a5e9b25aa29..8bf4962b708 100644
--- a/dlls/user32/caret.c
+++ b/dlls/user32/caret.c
@@ -274,7 +274,7 @@ BOOL WINAPI SetCaretPos( INT x, INT y )
         r.left = x;
         r.top = y;
         CARET_DisplayCaret( hwnd, &r );
-        SetSystemTimer( hwnd, TIMERID, Caret.timeout, CARET_Callback );
+        NtUserSetSystemTimer( hwnd, TIMERID, Caret.timeout, CARET_Callback );
     }
     return ret;
 }
@@ -352,7 +352,7 @@ BOOL WINAPI ShowCaret( HWND hwnd )
     if (ret && (hidden == 1))  /* hidden was 1 so it's now 0 */
     {
         CARET_DisplayCaret( hwnd, &r );
-        SetSystemTimer( hwnd, TIMERID, Caret.timeout, CARET_Callback );
+        NtUserSetSystemTimer( hwnd, TIMERID, Caret.timeout, CARET_Callback );
     }
     return ret;
 }
diff --git a/dlls/user32/input.c b/dlls/user32/input.c
index 4f7e44bff02..39e7ae17e13 100644
--- a/dlls/user32/input.c
+++ b/dlls/user32/input.c
@@ -862,7 +862,8 @@ TrackMouseEvent (TRACKMOUSEEVENT *ptme)
             /* Initialize HoverInfo variables even if not hover tracking */
             tracking_info.pos = pos;
 
-            timer = SetSystemTimer(tracking_info.tme.hwndTrack, (UINT_PTR)&tracking_info.tme, hover_time, TrackMouseEventProc);
+            timer = NtUserSetSystemTimer( tracking_info.tme.hwndTrack, (UINT_PTR)&tracking_info.tme,
+                                          hover_time, TrackMouseEventProc );
         }
     }
 
diff --git a/dlls/user32/listbox.c b/dlls/user32/listbox.c
index ff86ea1a7f9..32c9273945b 100644
--- a/dlls/user32/listbox.c
+++ b/dlls/user32/listbox.c
@@ -2413,7 +2413,7 @@ static void LISTBOX_HandleMouseMove( LB_DESCR *descr,
     /* Start/stop the system timer */
 
     if (dir != LB_TIMER_NONE)
-        SetSystemTimer( descr->self, LB_TIMER_ID, LB_SCROLL_TIMEOUT, NULL);
+        NtUserSetSystemTimer( descr->self, LB_TIMER_ID, LB_SCROLL_TIMEOUT, NULL);
     else if (LISTBOX_Timer != LB_TIMER_NONE)
         KillSystemTimer( descr->self, LB_TIMER_ID );
     LISTBOX_Timer = dir;
diff --git a/dlls/user32/message.c b/dlls/user32/message.c
index da0abef9469..eee4759513a 100644
--- a/dlls/user32/message.c
+++ b/dlls/user32/message.c
@@ -4417,39 +4417,6 @@ UINT_PTR WINAPI SetTimer( HWND hwnd, UINT_PTR id, UINT timeout, TIMERPROC proc )
 }
 
 
-/***********************************************************************
- *		SetSystemTimer (USER32.@)
- */
-UINT_PTR WINAPI SetSystemTimer( HWND hwnd, UINT_PTR id, UINT timeout, TIMERPROC proc )
-{
-    UINT_PTR ret;
-    WNDPROC winproc = 0;
-
-    if (proc) winproc = WINPROC_AllocProc( (WNDPROC)proc, FALSE );
-
-    timeout = min( max( USER_TIMER_MINIMUM, timeout ), USER_TIMER_MAXIMUM );
-
-    SERVER_START_REQ( set_win_timer )
-    {
-        req->win    = wine_server_user_handle( hwnd );
-        req->msg    = WM_SYSTIMER;
-        req->id     = id;
-        req->rate   = timeout;
-        req->lparam = (ULONG_PTR)winproc;
-        if (!wine_server_call_err( req ))
-        {
-            ret = reply->id;
-            if (!ret) ret = TRUE;
-        }
-        else ret = 0;
-    }
-    SERVER_END_REQ;
-
-    TRACE("Added %p %lx %p timeout %d\n", hwnd, id, winproc, timeout );
-    return ret;
-}
-
-
 /***********************************************************************
  *		KillTimer (USER32.@)
  */
diff --git a/dlls/user32/scroll.c b/dlls/user32/scroll.c
index a07737009e5..d666707299f 100644
--- a/dlls/user32/scroll.c
+++ b/dlls/user32/scroll.c
@@ -949,8 +949,8 @@ void SCROLL_HandleScrollEvent( HWND hwnd, INT nBar, UINT msg, POINT pt )
                                 SB_LINEUP, (LPARAM)hwndCtl );
 	    }
 
-	    SetSystemTimer( hwnd, SCROLL_TIMER, (msg == WM_LBUTTONDOWN) ?
-                            SCROLL_FIRST_DELAY : SCROLL_REPEAT_DELAY, NULL );
+	    NtUserSetSystemTimer( hwnd, SCROLL_TIMER, (msg == WM_LBUTTONDOWN) ?
+                                  SCROLL_FIRST_DELAY : SCROLL_REPEAT_DELAY, NULL );
         }
         else KillSystemTimer( hwnd, SCROLL_TIMER );
         break;
@@ -964,8 +964,8 @@ void SCROLL_HandleScrollEvent( HWND hwnd, INT nBar, UINT msg, POINT pt )
                 SendMessageW( hwndOwner, vertical ? WM_VSCROLL : WM_HSCROLL,
                                 SB_PAGEUP, (LPARAM)hwndCtl );
             }
-            SetSystemTimer( hwnd, SCROLL_TIMER, (msg == WM_LBUTTONDOWN) ?
-                              SCROLL_FIRST_DELAY : SCROLL_REPEAT_DELAY, NULL );
+            NtUserSetSystemTimer( hwnd, SCROLL_TIMER, (msg == WM_LBUTTONDOWN) ?
+                                  SCROLL_FIRST_DELAY : SCROLL_REPEAT_DELAY, NULL );
         }
         else KillSystemTimer( hwnd, SCROLL_TIMER );
         break;
@@ -1022,8 +1022,8 @@ void SCROLL_HandleScrollEvent( HWND hwnd, INT nBar, UINT msg, POINT pt )
                 SendMessageW( hwndOwner, vertical ? WM_VSCROLL : WM_HSCROLL,
                                 SB_PAGEDOWN, (LPARAM)hwndCtl );
             }
-            SetSystemTimer( hwnd, SCROLL_TIMER, (msg == WM_LBUTTONDOWN) ?
-                              SCROLL_FIRST_DELAY : SCROLL_REPEAT_DELAY, NULL );
+            NtUserSetSystemTimer( hwnd, SCROLL_TIMER, (msg == WM_LBUTTONDOWN) ?
+                                  SCROLL_FIRST_DELAY : SCROLL_REPEAT_DELAY, NULL );
         }
         else KillSystemTimer( hwnd, SCROLL_TIMER );
         break;
@@ -1038,8 +1038,8 @@ void SCROLL_HandleScrollEvent( HWND hwnd, INT nBar, UINT msg, POINT pt )
                                 SB_LINEDOWN, (LPARAM)hwndCtl );
 	    }
 
-	    SetSystemTimer( hwnd, SCROLL_TIMER, (msg == WM_LBUTTONDOWN) ?
-                            SCROLL_FIRST_DELAY : SCROLL_REPEAT_DELAY, NULL );
+	    NtUserSetSystemTimer( hwnd, SCROLL_TIMER, (msg == WM_LBUTTONDOWN) ?
+                                  SCROLL_FIRST_DELAY : SCROLL_REPEAT_DELAY, NULL );
         }
         else KillSystemTimer( hwnd, SCROLL_TIMER );
         break;
diff --git a/dlls/user32/user32.spec b/dlls/user32/user32.spec
index 7f27a0731a2..c5ea5e6c4c0 100644
--- a/dlls/user32/user32.spec
+++ b/dlls/user32/user32.spec
@@ -707,7 +707,7 @@
 @ stdcall SetSysColorsTemp(ptr ptr long)
 @ stdcall SetSystemCursor(long long)
 @ stdcall SetSystemMenu(long long)
-@ stdcall SetSystemTimer(long long long ptr)
+@ stdcall SetSystemTimer(long long long ptr) NtUserSetSystemTimer
 @ stdcall SetTaskmanWindow (long)
 @ stdcall SetThreadDesktop(long) NtUserSetThreadDesktop
 @ stdcall SetThreadDpiAwarenessContext(ptr)
diff --git a/dlls/user32/user_private.h b/dlls/user32/user_private.h
index 465522e54dc..d512ecb1501 100644
--- a/dlls/user32/user_private.h
+++ b/dlls/user32/user_private.h
@@ -36,9 +36,6 @@
 #define GET_DWORD(ptr) (*(const DWORD *)(ptr))
 #define GET_LONG(ptr) (*(const LONG *)(ptr))
 
-#define WM_SYSTIMER	    0x0118
-#define WM_POPUPSYSTEMMENU  0x0313
-
 #define WINE_MOUSE_HANDLE       ((HANDLE)1)
 #define WINE_KEYBOARD_HANDLE    ((HANDLE)2)
 
@@ -132,7 +129,6 @@ typedef LRESULT (*winproc_callback_t)( HWND hwnd, UINT msg, WPARAM wp, LPARAM lp
                                        LRESULT *result, void *arg );
 
 extern WNDPROC WINPROC_GetProc( WNDPROC proc, BOOL unicode ) DECLSPEC_HIDDEN;
-extern WNDPROC WINPROC_AllocProc( WNDPROC func, BOOL unicode ) DECLSPEC_HIDDEN;
 extern BOOL WINPROC_IsUnicode( WNDPROC proc, BOOL def_val ) DECLSPEC_HIDDEN;
 
 extern LRESULT WINPROC_CallProcAtoW( winproc_callback_t callback, HWND hwnd, UINT msg,
diff --git a/dlls/user32/winproc.c b/dlls/user32/winproc.c
index abca1d50e97..b489dadcda6 100644
--- a/dlls/user32/winproc.c
+++ b/dlls/user32/winproc.c
@@ -193,7 +193,7 @@ WNDPROC WINPROC_GetProc( WNDPROC proc, BOOL unicode )
  * lot of windows, it will usually only have a limited number of window procedures, so the
  * array won't grow too large, and this way we avoid the need to track allocations per window.
  */
-WNDPROC WINPROC_AllocProc( WNDPROC func, BOOL unicode )
+static WNDPROC WINPROC_AllocProc( WNDPROC func, BOOL unicode )
 {
     return (WNDPROC)NtUserCallTwoParam( (UINT_PTR)func, !unicode, NtUserAllocWinProc );
 }
diff --git a/dlls/win32u/message.c b/dlls/win32u/message.c
index e895f65c652..5fb238566f3 100644
--- a/dlls/win32u/message.c
+++ b/dlls/win32u/message.c
@@ -160,6 +160,38 @@ UINT_PTR WINAPI NtUserSetTimer( HWND hwnd, UINT_PTR id, UINT timeout, TIMERPROC
     return ret;
 }
 
+/***********************************************************************
+ *           NtUserSetSystemTimer (win32u.@)
+ */
+UINT_PTR WINAPI NtUserSetSystemTimer( HWND hwnd, UINT_PTR id, UINT timeout, TIMERPROC proc )
+{
+    UINT_PTR ret;
+    WNDPROC winproc = 0;
+
+    if (proc) winproc = alloc_winproc( (WNDPROC)proc, TRUE );
+
+    timeout = min( max( USER_TIMER_MINIMUM, timeout ), USER_TIMER_MAXIMUM );
+
+    SERVER_START_REQ( set_win_timer )
+    {
+        req->win    = wine_server_user_handle( hwnd );
+        req->msg    = WM_SYSTIMER;
+        req->id     = id;
+        req->rate   = timeout;
+        req->lparam = (ULONG_PTR)winproc;
+        if (!wine_server_call_err( req ))
+        {
+            ret = reply->id;
+            if (!ret) ret = TRUE;
+        }
+        else ret = 0;
+    }
+    SERVER_END_REQ;
+
+    TRACE( "Added %p %lx %p timeout %d\n", hwnd, id, winproc, timeout );
+    return ret;
+}
+
 /* see SendMessageW */
 LRESULT send_message( HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam )
 {
diff --git a/dlls/win32u/ntuser_private.h b/dlls/win32u/ntuser_private.h
index 6b0345461ea..d6c3e681c2f 100644
--- a/dlls/win32u/ntuser_private.h
+++ b/dlls/win32u/ntuser_private.h
@@ -49,6 +49,9 @@ struct user_callbacks
                                   const RECT *valid_rects );
 };
 
+#define WM_SYSTIMER         0x0118
+#define WM_POPUPSYSTEMMENU  0x0313
+
 struct user_object
 {
     HANDLE       handle;
diff --git a/dlls/win32u/syscall.c b/dlls/win32u/syscall.c
index b167ecc9680..5dbf6f43ac6 100644
--- a/dlls/win32u/syscall.c
+++ b/dlls/win32u/syscall.c
@@ -153,6 +153,7 @@ static void * const syscalls[] =
     NtUserSetProcessDpiAwarenessContext,
     NtUserSetProcessWindowStation,
     NtUserSetProp,
+    NtUserSetSystemTimer,
     NtUserSetThreadDesktop,
     NtUserSetTimer,
     NtUserSetWinEventHook,
diff --git a/dlls/win32u/win32u.spec b/dlls/win32u/win32u.spec
index 7d4599f0241..9c6103b84f8 100644
--- a/dlls/win32u/win32u.spec
+++ b/dlls/win32u/win32u.spec
@@ -1230,7 +1230,7 @@
 @ stdcall NtUserSetSysColors(long ptr ptr)
 @ stub NtUserSetSystemCursor
 @ stub NtUserSetSystemMenu
-@ stub NtUserSetSystemTimer
+@ stdcall -syscall NtUserSetSystemTimer(long long long ptr)
 @ stub NtUserSetTargetForResourceBrokering
 @ stdcall -syscall NtUserSetThreadDesktop(long)
 @ stub NtUserSetThreadInputBlocked
diff --git a/dlls/wow64win/syscall.h b/dlls/wow64win/syscall.h
index 3ded58962b8..4b181ecba89 100644
--- a/dlls/wow64win/syscall.h
+++ b/dlls/wow64win/syscall.h
@@ -138,6 +138,7 @@
     SYSCALL_ENTRY( NtUserSetProcessDpiAwarenessContext ) \
     SYSCALL_ENTRY( NtUserSetProcessWindowStation ) \
     SYSCALL_ENTRY( NtUserSetProp ) \
+    SYSCALL_ENTRY( NtUserSetSystemTimer ) \
     SYSCALL_ENTRY( NtUserSetThreadDesktop ) \
     SYSCALL_ENTRY( NtUserSetTimer ) \
     SYSCALL_ENTRY( NtUserSetWinEventHook ) \
diff --git a/dlls/wow64win/user.c b/dlls/wow64win/user.c
index c9f81d86672..2af7f9a3115 100644
--- a/dlls/wow64win/user.c
+++ b/dlls/wow64win/user.c
@@ -533,6 +533,16 @@ NTSTATUS WINAPI wow64_NtUserGetGUIThreadInfo( UINT *args )
     return TRUE;
 }
 
+NTSTATUS WINAPI wow64_NtUserSetSystemTimer( UINT *args )
+{
+    HWND hwnd = get_handle( &args );
+    UINT_PTR id = get_ulong( &args );
+    UINT timeout = get_ulong( &args );
+    TIMERPROC proc = get_ptr( &args );
+
+    return NtUserSetSystemTimer( hwnd, id, timeout, proc );
+}
+
 NTSTATUS WINAPI wow64_NtUserSetTimer( UINT *args )
 {
     HWND hwnd = get_handle( &args );
diff --git a/include/ntuser.h b/include/ntuser.h
index a055aa47905..afa4d0d561f 100644
--- a/include/ntuser.h
+++ b/include/ntuser.h
@@ -402,6 +402,7 @@ BOOL    WINAPI NtUserSetProcessDpiAwarenessContext( ULONG awareness, ULONG unkno
 BOOL    WINAPI NtUserSetProcessWindowStation( HWINSTA handle );
 BOOL    WINAPI NtUserSetProp( HWND hwnd, const WCHAR *str, HANDLE handle );
 BOOL    WINAPI NtUserSetSysColors( INT count, const INT *colors, const COLORREF *values );
+UINT_PTR WINAPI NtUserSetSystemTimer( HWND hwnd, UINT_PTR id, UINT timeout, TIMERPROC proc );
 BOOL    WINAPI NtUserSetThreadDesktop( HDESK handle );
 UINT_PTR WINAPI NtUserSetTimer( HWND hwnd, UINT_PTR id, UINT timeout, TIMERPROC proc, ULONG tolerance );
 LONG    WINAPI NtUserSetWindowLong( HWND hwnd, INT offset, LONG newval, BOOL ansi );