diff --git a/extension/script/backend/worker/eval/readonly.lua b/extension/script/backend/worker/eval/readonly.lua
index 49e01d45..ecce35cd 100644
--- a/extension/script/backend/worker/eval/readonly.lua
+++ b/extension/script/backend/worker/eval/readonly.lua
@@ -33,6 +33,9 @@ do
 		i = i + 1
 	end
 end
+if not env and getfenv then
+	env = getfenv(f)
+end
 do
 	local i = 1
 	while true do
@@ -76,6 +79,9 @@ end
 local compiled = env
 	and assert(_load(full_source, '=(EVAL)', "t", env))
 	or  assert(_load(full_source, '=(EVAL)'))
+if env and setfenv then
+	setfenv(compiled, env)
+end
 local func = compiled()
 do
 	local i = 1
diff --git a/extension/script/backend/worker/eval/readwrite.lua b/extension/script/backend/worker/eval/readwrite.lua
index 4073c181..12b41473 100644
--- a/extension/script/backend/worker/eval/readwrite.lua
+++ b/extension/script/backend/worker/eval/readwrite.lua
@@ -42,6 +42,9 @@ do
 		i = i + 1
 	end
 end
+if not env and getfenv then
+	env = getfenv(f)
+end
 do
 	local i = 1
 	while true do
@@ -90,6 +93,9 @@ end
 local compiled = env
 	and assert(_load(full_source, '=(EVAL)', "t", env))
 	or  assert(_load(full_source, '=(EVAL)'))
+if env and setfenv then
+	setfenv(compiled, env)
+end
 local func, update = compiled()
 local found = {}
 do
diff --git a/extension/script/backend/worker/variables.lua b/extension/script/backend/worker/variables.lua
index a42a4874..d8d472af 100644
--- a/extension/script/backend/worker/variables.lua
+++ b/extension/script/backend/worker/variables.lua
@@ -148,6 +148,13 @@ function special_has.Global(frameId)
     if eval ~= "_ENV" then
         eval = "_G"
         value = rdebug._G
+        if LUAVERSION == 51 then
+            local fenv = rdebug.getfenv(info.func)
+            if fenv and not rdebug.equal(fenv, rdebug._G) then
+                eval = nil
+                value = fenv
+            end
+        end
     end
     if eval == "_G" and globalCache._G then
         local t = globalCache._G
diff --git a/src/luadebug/rdebug_visitor.cpp b/src/luadebug/rdebug_visitor.cpp
index a0cd45fe..739e6dad 100644
--- a/src/luadebug/rdebug_visitor.cpp
+++ b/src/luadebug/rdebug_visitor.cpp
@@ -792,6 +792,19 @@ namespace luadebug::visitor {
         return 2;
     }
 
+    static int visitor_getfenv(luadbg_State* L, lua_State* hL, protected_area& area) {
+#if LUA_VERSION_NUM == 501
+        if (!copy_from_dbg(L, hL, area, 1, LUADBG_TFUNCTION)) {
+            return 0;
+        }
+        lua_pop(hL, 1);
+        refvalue::create(L, 1, refvalue::FENV {});
+        return 1;
+#else
+        return 0;
+#endif
+    }
+
     template <bool getref = true>
     static int visitor_getmetatable(luadbg_State* L, lua_State* hL, protected_area& area) {
         area.check_client_stack(2);
@@ -1120,6 +1133,7 @@ namespace luadebug::visitor {
             { "getlocalv", protected_call<visitor_getlocal<false>> },
             { "getupvalue", protected_call<visitor_getupvalue> },
             { "getupvaluev", protected_call<visitor_getupvalue<false>> },
+            { "getfenv", protected_call<visitor_getfenv> },
             { "getmetatable", protected_call<visitor_getmetatable> },
             { "getmetatablev", protected_call<visitor_getmetatable<false>> },
             { "getuservalue", protected_call<visitor_getuservalue> },
diff --git a/src/luadebug/util/refvalue.cpp b/src/luadebug/util/refvalue.cpp
index 6053e87f..ec644a87 100644
--- a/src/luadebug/util/refvalue.cpp
+++ b/src/luadebug/util/refvalue.cpp
@@ -328,6 +328,25 @@ namespace luadebug::refvalue {
         }
     }
 
+    template <>
+    int eval<FENV>(FENV& v, lua_State* hL, value* parent) {
+        int t = eval(parent, hL);
+        if (t == LUA_TNONE)
+            return LUA_TNONE;
+        if (t != LUA_TFUNCTION) {
+            lua_pop(hL, 1);
+            return LUA_TNONE;
+        }
+#if LUA_VERSION_NUM == 501
+        lua_getfenv(hL, -1);
+        lua_replace(hL, -2);
+        return lua_type(hL, -1);
+#else
+        lua_pop(hL, 1);
+        return LUA_TNONE;
+#endif
+    }
+
     int eval(value* v, lua_State* hL) {
         return visit([hL, v](auto&& arg) { return eval(arg, hL, v + 1); }, *v);
     }
diff --git a/src/luadebug/util/refvalue.h b/src/luadebug/util/refvalue.h
index 7d77f371..d2902c6e 100644
--- a/src/luadebug/util/refvalue.h
+++ b/src/luadebug/util/refvalue.h
@@ -53,6 +53,7 @@ namespace luadebug::refvalue {
     struct USERDATA_VAL {
         unsigned int index;
     };
+    struct FENV {};
     using value = variant<
         FRAME_LOCAL,
         FRAME_FUNC,
@@ -66,7 +67,8 @@ namespace luadebug::refvalue {
         TABLE_HASH_KEY,
         TABLE_HASH_VAL,
         USERDATA_KEY,
-        USERDATA_VAL>;
+        USERDATA_VAL,
+        FENV>;
     static_assert(std::is_trivially_copyable_v<value>);
 
     template <typename T>
@@ -102,6 +104,8 @@ namespace luadebug::refvalue {
     struct allow_as_child<USERDATA_KEY> : public std::true_type {};
     template <>
     struct allow_as_child<USERDATA_VAL> : public std::true_type {};
+    template <>
+    struct allow_as_child<FENV> : public std::true_type {};
 
     int eval(value* v, lua_State* hL);
     bool assign(value* v, lua_State* hL);