diff --git a/scripts/build.sh b/scripts/build.sh
index edfb87b..1a81c68 100755
--- a/scripts/build.sh
+++ b/scripts/build.sh
@@ -32,6 +32,7 @@ if [[ "$1" == "lua-5.0.3" ]]; then
         '_luaL_loadbuffer', \
         '_lua_close', \
         '_lua_gettable', \
+        '_lua_gettop', \
         '_lua_insert', \
         '_lua_isstring', \
         '_lua_open', \
@@ -71,6 +72,7 @@ elif [[ "$1" == "lua-5.1.5" ]]; then
         '_lua_close', \
         '_lua_getfield', \
         '_lua_gettable', \
+		'_lua_gettop', \
         '_lua_insert', \
         '_lua_isstring', \
         '_lua_pcall', \
@@ -110,6 +112,7 @@ elif [[ "$1" == "lua-5.2.4" ]]; then
         '_lua_getfield', \
         '_lua_getglobal', \
         '_lua_gettable', \
+		'_lua_gettop', \
         '_lua_insert', \
         '_lua_isstring', \
         '_lua_pcallk', \
@@ -150,6 +153,7 @@ else
         '_lua_getfield', \
         '_lua_getglobal', \
         '_lua_gettable', \
+		'_lua_gettop', \
         '_lua_isstring', \
         '_lua_pcallk', \
         '_lua_pushstring', \
diff --git a/src/binding-factory.ts b/src/binding-factory.ts
index 930c777..ca5e49b 100644
--- a/src/binding-factory.ts
+++ b/src/binding-factory.ts
@@ -8,6 +8,7 @@ const luaBindings: Record<string, luaBindingFactoryFunc> = {
         return {
             lua_close: luaGlue.cwrap("lua_close", null, ["number"]),
             lua_gettable: luaGlue.cwrap("lua_gettable", "number", ["number", "number"]),
+            lua_gettop: luaGlue.cwrap("lua_gettop", "number", ["number"]),
             lua_isstring: luaGlue.cwrap("lua_isstring", "number", ["number", "number"]),
             // #define in all versions
             lua_pop: function(L: LuaState, n: number) {
diff --git a/src/lua.ts b/src/lua.ts
index 1a3380b..c27b7d7 100644
--- a/src/lua.ts
+++ b/src/lua.ts
@@ -29,6 +29,7 @@ export interface Lua {
     lua_getglobal(L: LuaState, name: string): number;
     // TODO returns int in some lua versions void in others
     lua_gettable(L: LuaState, index: number): number;
+	lua_gettop(L: LuaState): number;
     lua_insert(L: LuaState, index: number): void;
     lua_isstring(L: LuaState, index: number): number;
     lua_pcall(L: LuaState, nargs: number, nresults: number, msgh: number): number;