diff --git a/src/script/lua_api/l_mainmenu.cpp b/src/script/lua_api/l_mainmenu.cpp
index af27ade49..1c3172f59 100644
--- a/src/script/lua_api/l_mainmenu.cpp
+++ b/src/script/lua_api/l_mainmenu.cpp
@@ -938,6 +938,14 @@ int ModApiMainMenu::l_do_async_callback(lua_State *L)
 	return 1;
 }
 
+/******************************************************************************/
+int ModApiMainMenu::l_sleep_ms(lua_State *L)
+{
+	int delay = luaL_checkinteger(L, 1);
+	sleep_ms(delay);
+	return 0;
+}
+
 /******************************************************************************/
 void ModApiMainMenu::Initialize(lua_State *L, int top)
 {
@@ -1011,4 +1019,5 @@ void ModApiMainMenu::InitializeAsync(lua_State *L, int top)
 	API_FCT(get_min_supp_proto);
 	API_FCT(get_max_supp_proto);
 	//API_FCT(gettext); (gettext lib isn't threadsafe)
+	API_FCT(sleep_ms);
 }
diff --git a/src/script/lua_api/l_mainmenu.h b/src/script/lua_api/l_mainmenu.h
index f69f032bb..ddc450062 100644
--- a/src/script/lua_api/l_mainmenu.h
+++ b/src/script/lua_api/l_mainmenu.h
@@ -158,6 +158,8 @@ private:
 	// async
 	static int l_do_async_callback(lua_State *L);
 
+	static int l_sleep_ms(lua_State *L);
+
 public:
 
 	/**