diff --git a/sol/compatibility/5.1.0.h b/sol/compatibility/5.1.0.h
index 72ddd085..0050b24e 100644
--- a/sol/compatibility/5.1.0.h
+++ b/sol/compatibility/5.1.0.h
@@ -158,6 +158,9 @@ inline const char* kepler_lua_compat_get_string(lua_State* L, void* ud, size_t*
     return ls->s;
 }
 
+#if !defined(SOL_LUAJIT) || ((SOL_LUAJIT_VERSION - 020100) <= 0)
+// Luajit 2.1.0 has this function already
+
 inline int luaL_loadbufferx(lua_State* L, const char* buff, size_t size, const char* name, const char*) {
     kepler_lua_compat_get_string_view ls;
     ls.s = buff;
@@ -165,6 +168,8 @@ inline int luaL_loadbufferx(lua_State* L, const char* buff, size_t size, const c
     return lua_load(L, kepler_lua_compat_get_string, &ls, name/*, mode*/);
 }
 
+#endif // LuaJIT 2.1.x beta and beyond
+
 #endif /* Lua 5.1 */
 
 #endif // SOL_5_1_0_H
\ No newline at end of file
diff --git a/sol/compatibility/version.hpp b/sol/compatibility/version.hpp
index 6ec934b8..5ddc23d9 100644
--- a/sol/compatibility/version.hpp
+++ b/sol/compatibility/version.hpp
@@ -42,6 +42,7 @@
 #ifdef LUAJIT_VERSION
 #ifndef SOL_LUAJIT
 #define SOL_LUAJIT
+#define SOL_LUAJIT_VERSION LUAJIT_VERSION_NUM
 #endif // sol luajit
 #endif // luajit