diff --git a/CodeGen/src/CodeGenUtils.cpp b/CodeGen/src/CodeGenUtils.cpp
index c1a9c338..973829ca 100644
--- a/CodeGen/src/CodeGenUtils.cpp
+++ b/CodeGen/src/CodeGenUtils.cpp
@@ -71,7 +71,7 @@ bool forgLoopTableIter(lua_State* L, Table* h, int index, TValue* ra)
 
         if (!ttisnil(e))
         {
-            setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(index + 1)));
+            setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(index + 1)), LU_TAG_ITERATOR);
             setnvalue(ra + 3, double(index + 1));
             setobj2s(L, ra + 4, e);
 
@@ -90,7 +90,7 @@ bool forgLoopTableIter(lua_State* L, Table* h, int index, TValue* ra)
 
         if (!ttisnil(gval(n)))
         {
-            setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(index + 1)));
+            setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(index + 1)), LU_TAG_ITERATOR);
             getnodekey(L, ra + 3, n);
             setobj(L, ra + 4, gval(n));
 
@@ -115,7 +115,7 @@ bool forgLoopNodeIter(lua_State* L, Table* h, int index, TValue* ra)
 
         if (!ttisnil(gval(n)))
         {
-            setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(index + 1)));
+            setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(index + 1)), LU_TAG_ITERATOR);
             getnodekey(L, ra + 3, n);
             setobj(L, ra + 4, gval(n));
 
@@ -697,7 +697,7 @@ const Instruction* executeFORGPREP(lua_State* L, const Instruction* pc, StkId ba
         {
             // set up registers for builtin iteration
             setobj2s(L, ra + 1, ra);
-            setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(0)));
+            setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(0)), LU_TAG_ITERATOR);
             setnilvalue(ra);
         }
         else
diff --git a/VM/include/lua.h b/VM/include/lua.h
index dbf19cb4..0390de7c 100644
--- a/VM/include/lua.h
+++ b/VM/include/lua.h
@@ -159,9 +159,11 @@ LUA_API const char* lua_namecallatom(lua_State* L, int* atom);
 LUA_API int lua_objlen(lua_State* L, int idx);
 LUA_API lua_CFunction lua_tocfunction(lua_State* L, int idx);
 LUA_API void* lua_tolightuserdata(lua_State* L, int idx);
+LUA_API void* lua_tolightuserdatatagged(lua_State* L, int idx, int tag);
 LUA_API void* lua_touserdata(lua_State* L, int idx);
 LUA_API void* lua_touserdatatagged(lua_State* L, int idx, int tag);
 LUA_API int lua_userdatatag(lua_State* L, int idx);
+LUA_API int lua_lightuserdatatag(lua_State* L, int idx);
 LUA_API lua_State* lua_tothread(lua_State* L, int idx);
 LUA_API void* lua_tobuffer(lua_State* L, int idx, size_t* len);
 LUA_API const void* lua_topointer(lua_State* L, int idx);
@@ -186,7 +188,7 @@ LUA_API void lua_pushcclosurek(lua_State* L, lua_CFunction fn, const char* debug
 LUA_API void lua_pushboolean(lua_State* L, int b);
 LUA_API int lua_pushthread(lua_State* L);
 
-LUA_API void lua_pushlightuserdata(lua_State* L, void* p);
+LUA_API void lua_pushlightuserdatatagged(lua_State* L, void* p, int tag);
 LUA_API void* lua_newuserdatatagged(lua_State* L, size_t sz, int tag);
 LUA_API void* lua_newuserdatadtor(lua_State* L, size_t sz, void (*dtor)(void*));
 
@@ -323,6 +325,9 @@ typedef void (*lua_Destructor)(lua_State* L, void* userdata);
 LUA_API void lua_setuserdatadtor(lua_State* L, int tag, lua_Destructor dtor);
 LUA_API lua_Destructor lua_getuserdatadtor(lua_State* L, int tag);
 
+LUA_API void lua_setlightuserdataname(lua_State* L, int tag, const char* name);
+LUA_API const char* lua_getlightuserdataname(lua_State* L, int tag);
+
 LUA_API void lua_clonefunction(lua_State* L, int idx);
 
 LUA_API void lua_cleartable(lua_State* L, int idx);
@@ -370,6 +375,7 @@ LUA_API void lua_unref(lua_State* L, int ref);
 #define lua_pushliteral(L, s) lua_pushlstring(L, "" s, (sizeof(s) / sizeof(char)) - 1)
 #define lua_pushcfunction(L, fn, debugname) lua_pushcclosurek(L, fn, debugname, 0, NULL)
 #define lua_pushcclosure(L, fn, debugname, nup) lua_pushcclosurek(L, fn, debugname, nup, NULL)
+#define lua_pushlightuserdata(L, p) lua_pushlightuserdatatagged(L, p, 0)
 
 #define lua_setglobal(L, s) lua_setfield(L, LUA_GLOBALSINDEX, (s))
 #define lua_getglobal(L, s) lua_getfield(L, LUA_GLOBALSINDEX, (s))
diff --git a/VM/include/luaconf.h b/VM/include/luaconf.h
index 7a1bbb95..910e259a 100644
--- a/VM/include/luaconf.h
+++ b/VM/include/luaconf.h
@@ -101,6 +101,11 @@
 #define LUA_UTAG_LIMIT 128
 #endif
 
+// number of valid Lua lightuserdata tags
+#ifndef LUA_LUTAG_LIMIT
+#define LUA_LUTAG_LIMIT 128
+#endif
+
 // upper bound for number of size classes used by page allocator
 #ifndef LUA_SIZECLASSES
 #define LUA_SIZECLASSES 32
diff --git a/VM/src/lapi.cpp b/VM/src/lapi.cpp
index 355e4e21..58c767f1 100644
--- a/VM/src/lapi.cpp
+++ b/VM/src/lapi.cpp
@@ -505,6 +505,12 @@ void* lua_tolightuserdata(lua_State* L, int idx)
     return (!ttislightuserdata(o)) ? NULL : pvalue(o);
 }
 
+void* lua_tolightuserdatatagged(lua_State* L, int idx, int tag)
+{
+    StkId o = index2addr(L, idx);
+    return (!ttislightuserdata(o) || lightuserdatatag(o) != tag) ? NULL : pvalue(o);
+}
+
 void* lua_touserdata(lua_State* L, int idx)
 {
     StkId o = index2addr(L, idx);
@@ -530,6 +536,14 @@ int lua_userdatatag(lua_State* L, int idx)
     return -1;
 }
 
+int lua_lightuserdatatag(lua_State* L, int idx)
+{
+    StkId o = index2addr(L, idx);
+    if (ttislightuserdata(o))
+        return lightuserdatatag(o);
+    return -1;
+}
+
 lua_State* lua_tothread(lua_State* L, int idx)
 {
     StkId o = index2addr(L, idx);
@@ -665,9 +679,10 @@ void lua_pushboolean(lua_State* L, int b)
     api_incr_top(L);
 }
 
-void lua_pushlightuserdata(lua_State* L, void* p)
+void lua_pushlightuserdatatagged(lua_State* L, void* p, int tag)
 {
-    setpvalue(L->top, p);
+    api_check(L, unsigned(tag) < LUA_LUTAG_LIMIT);
+    setpvalue(L->top, p, tag);
     api_incr_top(L);
 }
 
@@ -1412,6 +1427,24 @@ lua_Destructor lua_getuserdatadtor(lua_State* L, int tag)
     return L->global->udatagc[tag];
 }
 
+void lua_setlightuserdataname(lua_State* L, int tag, const char* name)
+{
+    api_check(L, unsigned(tag) < LUA_LUTAG_LIMIT);
+    api_check(L, !L->global->lightuserdataname[tag]); // renaming not supported
+    if (!L->global->lightuserdataname[tag])
+    {
+        L->global->lightuserdataname[tag] = luaS_new(L, name);
+        luaS_fix(L->global->lightuserdataname[tag]); // never collect these names
+    }
+}
+
+const char* lua_getlightuserdataname(lua_State* L, int tag)
+{
+    api_check(L, unsigned(tag) < LUA_LUTAG_LIMIT);
+    const TString* name = L->global->lightuserdataname[tag];
+    return name ? getstr(name) : nullptr;
+}
+
 void lua_clonefunction(lua_State* L, int idx)
 {
     luaC_checkGC(L);
diff --git a/VM/src/lobject.cpp b/VM/src/lobject.cpp
index 88d8d7ca..081e3314 100644
--- a/VM/src/lobject.cpp
+++ b/VM/src/lobject.cpp
@@ -48,7 +48,7 @@ int luaO_rawequalObj(const TValue* t1, const TValue* t2)
         case LUA_TBOOLEAN:
             return bvalue(t1) == bvalue(t2); // boolean true must be 1 !!
         case LUA_TLIGHTUSERDATA:
-            return pvalue(t1) == pvalue(t2);
+            return pvalue(t1) == pvalue(t2) && (!FFlag::TaggedLuData || lightuserdatatag(t1) == lightuserdatatag(t2));
         default:
             LUAU_ASSERT(iscollectable(t1));
             return gcvalue(t1) == gcvalue(t2);
@@ -71,7 +71,7 @@ int luaO_rawequalKey(const TKey* t1, const TValue* t2)
         case LUA_TBOOLEAN:
             return bvalue(t1) == bvalue(t2); // boolean true must be 1 !!
         case LUA_TLIGHTUSERDATA:
-            return pvalue(t1) == pvalue(t2);
+            return pvalue(t1) == pvalue(t2) && (!FFlag::TaggedLuData || lightuserdatatag(t1) == lightuserdatatag(t2));
         default:
             LUAU_ASSERT(iscollectable(t1));
             return gcvalue(t1) == gcvalue(t2);
diff --git a/VM/src/lobject.h b/VM/src/lobject.h
index 71640140..d236f7e4 100644
--- a/VM/src/lobject.h
+++ b/VM/src/lobject.h
@@ -80,6 +80,11 @@ typedef struct lua_TValue
 
 #define l_isfalse(o) (ttisnil(o) || (ttisboolean(o) && bvalue(o) == 0))
 
+#define lightuserdatatag(o) check_exp(ttislightuserdata(o), (o)->extra[0])
+
+// Internal tags used by the VM
+#define LU_TAG_ITERATOR LUA_UTAG_LIMIT
+
 /*
 ** for internal debug only
 */
@@ -120,10 +125,11 @@ typedef struct lua_TValue
     }
 #endif
 
-#define setpvalue(obj, x) \
+#define setpvalue(obj, x, tag) \
     { \
         TValue* i_o = (obj); \
         i_o->value.p = (x); \
+        i_o->extra[0] = (tag); \
         i_o->tt = LUA_TLIGHTUSERDATA; \
     }
 
@@ -492,3 +498,5 @@ LUAI_FUNC int luaO_str2d(const char* s, double* result);
 LUAI_FUNC const char* luaO_pushvfstring(lua_State* L, const char* fmt, va_list argp);
 LUAI_FUNC const char* luaO_pushfstring(lua_State* L, const char* fmt, ...);
 LUAI_FUNC const char* luaO_chunkid(char* buf, size_t buflen, const char* source, size_t srclen);
+
+LUAU_FASTFLAG(TaggedLuData)
diff --git a/VM/src/lstate.cpp b/VM/src/lstate.cpp
index 161dcda0..858f61a3 100644
--- a/VM/src/lstate.cpp
+++ b/VM/src/lstate.cpp
@@ -210,6 +210,8 @@ lua_State* lua_newstate(lua_Alloc f, void* ud)
         g->mt[i] = NULL;
     for (i = 0; i < LUA_UTAG_LIMIT; i++)
         g->udatagc[i] = NULL;
+    for (i = 0; i < LUA_LUTAG_LIMIT; i++)
+        g->lightuserdataname[i] = NULL;
     for (i = 0; i < LUA_MEMORY_CATEGORIES; i++)
         g->memcatbytes[i] = 0;
 
diff --git a/VM/src/lstate.h b/VM/src/lstate.h
index ed73d3d8..2c6d35dc 100644
--- a/VM/src/lstate.h
+++ b/VM/src/lstate.h
@@ -214,6 +214,8 @@ typedef struct global_State
 
     void (*udatagc[LUA_UTAG_LIMIT])(lua_State*, void*); // for each userdata tag, a gc callback to be called immediately before freeing memory
 
+    TString* lightuserdataname[LUA_LUTAG_LIMIT]; // names for tagged lightuserdata
+
     GCStats gcstats;
 
 #ifdef LUAI_GCMETRICS
diff --git a/VM/src/ltm.cpp b/VM/src/ltm.cpp
index 927a535b..3a9fddaa 100644
--- a/VM/src/ltm.cpp
+++ b/VM/src/ltm.cpp
@@ -129,6 +129,18 @@ const TString* luaT_objtypenamestr(lua_State* L, const TValue* o)
         if (ttisstring(type))
             return tsvalue(type);
     }
+    else if (FFlag::TaggedLuData && ttislightuserdata(o))
+    {
+        int tag = lightuserdatatag(o);
+
+        if (unsigned(tag) < LUA_LUTAG_LIMIT)
+        {
+            const TString* name = L->global->lightuserdataname[tag];
+
+            if (name)
+                return name;
+        }
+    }
     else if (Table* mt = L->global->mt[ttype(o)])
     {
         const TValue* type = luaH_getstr(mt, L->global->tmname[TM_TYPE]);
diff --git a/VM/src/lvmexecute.cpp b/VM/src/lvmexecute.cpp
index c1a3ca8e..1c77fa14 100644
--- a/VM/src/lvmexecute.cpp
+++ b/VM/src/lvmexecute.cpp
@@ -135,6 +135,8 @@
 // Does VM support native execution via ExecutionCallbacks? We mostly assume it does but keep the define to make it easy to quantify the cost.
 #define VM_HAS_NATIVE 1
 
+LUAU_FASTFLAGVARIABLE(TaggedLuData, false)
+
 LUAU_NOINLINE void luau_callhook(lua_State* L, lua_Hook hook, void* userdata)
 {
     ptrdiff_t base = savestack(L, L->base);
@@ -1110,7 +1112,7 @@ reentry:
                         VM_NEXT();
 
                     case LUA_TLIGHTUSERDATA:
-                        pc += pvalue(ra) == pvalue(rb) ? LUAU_INSN_D(insn) : 1;
+                        pc += (pvalue(ra) == pvalue(rb) && (!FFlag::TaggedLuData || lightuserdatatag(ra) == lightuserdatatag(rb))) ? LUAU_INSN_D(insn) : 1;
                         LUAU_ASSERT(unsigned(pc - cl->l.p->code) < unsigned(cl->l.p->sizecode));
                         VM_NEXT();
 
@@ -1225,7 +1227,7 @@ reentry:
                         VM_NEXT();
 
                     case LUA_TLIGHTUSERDATA:
-                        pc += pvalue(ra) != pvalue(rb) ? LUAU_INSN_D(insn) : 1;
+                        pc += (pvalue(ra) != pvalue(rb) || (FFlag::TaggedLuData && lightuserdatatag(ra) != lightuserdatatag(rb))) ? LUAU_INSN_D(insn) : 1;
                         LUAU_ASSERT(unsigned(pc - cl->l.p->code) < unsigned(cl->l.p->sizecode));
                         VM_NEXT();
 
@@ -2296,7 +2298,7 @@ reentry:
                     {
                         // set up registers for builtin iteration
                         setobj2s(L, ra + 1, ra);
-                        setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(0)));
+                        setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(0)), LU_TAG_ITERATOR);
                         setnilvalue(ra);
                     }
                     else
@@ -2348,7 +2350,7 @@ reentry:
 
                         if (!ttisnil(e))
                         {
-                            setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(index + 1)));
+                            setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(index + 1)), LU_TAG_ITERATOR);
                             setnvalue(ra + 3, double(index + 1));
                             setobj2s(L, ra + 4, e);
 
@@ -2369,7 +2371,7 @@ reentry:
 
                         if (!ttisnil(gval(n)))
                         {
-                            setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(index + 1)));
+                            setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(index + 1)), LU_TAG_ITERATOR);
                             getnodekey(L, ra + 3, n);
                             setobj2s(L, ra + 4, gval(n));
 
@@ -2421,7 +2423,7 @@ reentry:
                 {
                     setnilvalue(ra);
                     // ra+1 is already the table
-                    setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(0)));
+                    setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(0)), LU_TAG_ITERATOR);
                 }
                 else if (!ttisfunction(ra))
                 {
@@ -2450,7 +2452,7 @@ reentry:
                 {
                     setnilvalue(ra);
                     // ra+1 is already the table
-                    setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(0)));
+                    setpvalue(ra + 2, reinterpret_cast<void*>(uintptr_t(0)), LU_TAG_ITERATOR);
                 }
                 else if (!ttisfunction(ra))
                 {
diff --git a/VM/src/lvmutils.cpp b/VM/src/lvmutils.cpp
index c4b0b47d..851d778c 100644
--- a/VM/src/lvmutils.cpp
+++ b/VM/src/lvmutils.cpp
@@ -288,7 +288,7 @@ int luaV_equalval(lua_State* L, const TValue* t1, const TValue* t2)
     case LUA_TBOOLEAN:
         return bvalue(t1) == bvalue(t2); // true must be 1 !!
     case LUA_TLIGHTUSERDATA:
-        return pvalue(t1) == pvalue(t2);
+        return pvalue(t1) == pvalue(t2) && (!FFlag::TaggedLuData || lightuserdatatag(t1) == lightuserdatatag(t2));
     case LUA_TUSERDATA:
     {
         tm = get_compTM(L, uvalue(t1)->metatable, uvalue(t2)->metatable, TM_EQ);
diff --git a/tests/Conformance.test.cpp b/tests/Conformance.test.cpp
index a9c5bc37..b530ce55 100644
--- a/tests/Conformance.test.cpp
+++ b/tests/Conformance.test.cpp
@@ -32,6 +32,7 @@ LUAU_FASTFLAG(LuauBufferDefinitions);
 LUAU_FASTFLAG(LuauCodeGenFixByteLower);
 LUAU_FASTFLAG(LuauCompileBufferAnnotation);
 LUAU_FASTFLAG(LuauLoopInterruptFix);
+LUAU_FASTFLAG(TaggedLuData);
 LUAU_DYNAMIC_FASTFLAG(LuauStricterUtf8);
 LUAU_FASTINT(CodegenHeuristicsInstructionLimit);
 
@@ -1700,6 +1701,32 @@ TEST_CASE("UserdataApi")
     CHECK(dtorhits == 42);
 }
 
+TEST_CASE("LightuserdataApi")
+{
+    ScopedFastFlag taggedLuData{FFlag::TaggedLuData, true};
+
+    StateRef globalState(luaL_newstate(), lua_close);
+    lua_State* L = globalState.get();
+
+    void* value = (void*)0x12345678;
+
+    lua_pushlightuserdatatagged(L, value, 1);
+    CHECK(lua_lightuserdatatag(L, -1) == 1);
+    CHECK(lua_tolightuserdatatagged(L, -1, 0) == nullptr);
+    CHECK(lua_tolightuserdatatagged(L, -1, 1) == value);
+
+    lua_setlightuserdataname(L, 1, "id");
+    CHECK(!lua_getlightuserdataname(L, 0));
+    CHECK(strcmp(lua_getlightuserdataname(L, 1), "id") == 0);
+    CHECK(strcmp(luaL_typename(L, -1), "id") == 0);
+
+    lua_pushlightuserdatatagged(L, value, 0);
+    lua_pushlightuserdatatagged(L, value, 1);
+    CHECK(lua_rawequal(L, -1, -2) == 0);
+
+    globalState.reset();
+}
+
 TEST_CASE("Iter")
 {
     runConformance("iter.lua");