diff --git a/README.md b/README.md
index 95dae741..35dd5526 100644
--- a/README.md
+++ b/README.md
@@ -66,7 +66,18 @@ In the browser `require` and `package.loadlib` try to find a file by making sync
 
 ### _Missing_ features
 
-- `lua_gc`/`collectgarbage`: Fengari relies on the JS garbage collector and does not implement its own.
+- `lua_gc`/`collectgarbage`: These functions only work when the JS garbage collector is available in the current environment:
+    - `LUA_GCCOLLECT`
+        - Supported in IE via `CollectGarbage`
+        - Supported in Opera < 15 via `opera.collect`
+        - Only supported in v8 engines (e.g. node.js, Chrome) if the process was started with `--expose-gc`
+    - `LUA_GCSTEP`
+        - Only supported in v8 engines (e.g. node.js, Chrome) if the process was started with `--expose-gc`
+    - `LUA_GCCOUNT`, `LUA_GCCOUNTB`
+        - Supported in WebKit browsers via `performance.memory`
+        - Supported in node.js via the [`v8` library](https://nodejs.org/api/v8.html)
+    - `LUA_GCSTOP`, `LUA_GCSETPAUSE`, `LUA_GCSETSTEPMUL`
+        - Supported in node.js via the [`v8` library](https://nodejs.org/api/v8.html)
 - The following functions are only available in Node:
     - The entire `io` lib
     - `os.remove`
diff --git a/src/defs.js b/src/defs.js
index daa5f702..17f287cb 100644
--- a/src/defs.js
+++ b/src/defs.js
@@ -327,6 +327,16 @@ const LUA_OPEQ = 0;
 const LUA_OPLT = 1;
 const LUA_OPLE = 2;
 
+const LUA_GCSTOP       = 0;
+const LUA_GCRESTART    = 1;
+const LUA_GCCOLLECT    = 2;
+const LUA_GCCOUNT      = 3;
+const LUA_GCCOUNTB     = 4;
+const LUA_GCSTEP       = 5;
+const LUA_GCSETPAUSE   = 6;
+const LUA_GCSETSTEPMUL = 7;
+const LUA_GCISRUNNING  = 9;
+
 const LUA_MINSTACK = 20;
 
 const { LUAI_MAXSTACK } = require('./luaconf.js');
@@ -379,6 +389,16 @@ const LUA_MASKRET   = (1 << LUA_HOOKRET);
 const LUA_MASKLINE  = (1 << LUA_HOOKLINE);
 const LUA_MASKCOUNT = (1 << LUA_HOOKCOUNT);
 
+
+module.exports.LUA_GCCOLLECT           = LUA_GCCOLLECT;
+module.exports.LUA_GCCOUNT             = LUA_GCCOUNT;
+module.exports.LUA_GCCOUNTB            = LUA_GCCOUNTB;
+module.exports.LUA_GCISRUNNING         = LUA_GCISRUNNING;
+module.exports.LUA_GCRESTART           = LUA_GCRESTART;
+module.exports.LUA_GCSETPAUSE          = LUA_GCSETPAUSE;
+module.exports.LUA_GCSETSTEPMUL        = LUA_GCSETSTEPMUL;
+module.exports.LUA_GCSTEP              = LUA_GCSTEP;
+module.exports.LUA_GCSTOP              = LUA_GCSTOP;
 module.exports.LUA_HOOKCALL            = LUA_HOOKCALL;
 module.exports.LUA_HOOKCOUNT           = LUA_HOOKCOUNT;
 module.exports.LUA_HOOKLINE            = LUA_HOOKLINE;
diff --git a/src/lapi.js b/src/lapi.js
index 7443fb78..3d253e89 100644
--- a/src/lapi.js
+++ b/src/lapi.js
@@ -1,6 +1,15 @@
 "use strict";
 
 const {
+    LUA_GCCOLLECT,
+    LUA_GCCOUNT,
+    LUA_GCCOUNTB,
+    LUA_GCISRUNNING,
+    LUA_GCRESTART,
+    LUA_GCSETPAUSE,
+    LUA_GCSETSTEPMUL,
+    LUA_GCSTEP,
+    LUA_GCSTOP,
     LUA_MULTRET,
     LUA_OPBNOT,
     LUA_OPEQ,
@@ -1101,8 +1110,91 @@ const lua_upvaluejoin = function(L, fidx1, n1, fidx2, n2) {
     ref1.f.upvals[ref1.i] = up2;
 };
 
-// This functions are only there for compatibility purposes
-const lua_gc = function () {};
+const lua_gc = function (L, what, data) {
+    switch (what) {
+        case LUA_GCSTOP: {
+            if (typeof process !== "undefined") {
+                /* we can't stop the v8 GC */
+                /* but we can slow it down to effectivly 0... */
+                require("v8").setFlagsFromString("--gc_interval="+0xFFFFFFFF);
+                return 0;
+            }
+            return -1;
+        }
+        case LUA_GCRESTART: {
+            return -1;
+        }
+        case LUA_GCCOLLECT: {
+            if (typeof gc === "function") {
+                /* v8 when started with --expose-gc */
+                /* global gc */
+                gc(false);
+            } else if (typeof CollectGarbage === "function") {
+                /* IE */
+                /* global CollectGarbage */
+                CollectGarbage();
+            } else if (typeof opera !== "undefined" && typeof opera.collect === "function") {
+                /* global opera */
+                opera.collect();
+            } else {
+                return -1;
+            }
+            return 0;
+        }
+        case LUA_GCCOUNT: {
+            /* GC values are expressed in Kbytes: #bytes/2^10 */
+            let v;
+            if (typeof process !== "undefined") {
+                v = require("v8").getHeapStatistics().used_heap_size;
+            } else if (typeof performance !== "undefined" && typeof performance.memory === "object") {
+                v = performance.memory.usedJSHeapSize;
+            } else {
+                return -1;
+            }
+            return v >> 10;
+        }
+        case LUA_GCCOUNTB: {
+            let v;
+            if (typeof process !== "undefined") {
+                v = require("v8").getHeapStatistics().used_heap_size;
+            } else if (typeof performance !== "undefined" && typeof performance.memory === "object") {
+                v = performance.memory.usedJSHeapSize;
+            } else {
+                return -1;
+            }
+            return v & 0x3ff;
+        }
+        case LUA_GCSTEP: {
+            if (typeof gc === "function") {
+                /* global gc */
+                gc(true);
+                return 0;
+            }
+            return -1;
+        }
+        case LUA_GCSETPAUSE: {
+            if (typeof process !== "undefined") {
+                require("v8").setFlagsFromString("--gc_interval="+data);
+                /* we can't get the current gc_interval */
+                return 0;
+            }
+            return -1;
+        }
+        case LUA_GCSETSTEPMUL: {
+            if (typeof process !== "undefined") {
+                require("v8").setFlagsFromString("--max_old_space_size="+data);
+                return 0;
+            }
+            return -1;
+        }
+        case LUA_GCISRUNNING: {
+            /* we can't stop the JS GC */
+            /* we can't get the current gc_interval */
+            return 1;
+        }
+        default: return -1;  /* invalid option */
+    }
+};
 
 const lua_getallocf = function () {
     console.warn("lua_getallocf is not available");
diff --git a/src/lbaselib.js b/src/lbaselib.js
index 63754efe..7cf1588d 100644
--- a/src/lbaselib.js
+++ b/src/lbaselib.js
@@ -1,6 +1,15 @@
 "use strict";
 
 const {
+    LUA_GCCOLLECT,
+    LUA_GCCOUNT,
+    LUA_GCCOUNTB,
+    LUA_GCISRUNNING,
+    LUA_GCRESTART,
+    LUA_GCSETPAUSE,
+    LUA_GCSETSTEPMUL,
+    LUA_GCSTEP,
+    LUA_GCSTOP,
     LUA_MULTRET,
     LUA_OK,
     LUA_TFUNCTION,
@@ -15,6 +24,7 @@ const {
     lua_callk,
     lua_concat,
     lua_error,
+    lua_gc,
     lua_getglobal,
     lua_geti,
     lua_getmetatable,
@@ -33,6 +43,7 @@ const {
     lua_pushinteger,
     lua_pushliteral,
     lua_pushnil,
+    lua_pushnumber,
     lua_pushstring,
     lua_pushvalue,
     lua_rawequal,
@@ -200,10 +211,30 @@ const opts = [
     "count", "step", "setpause", "setstepmul",
     "isrunning"
 ].map((e) => to_luastring(e));
+const optsnum = [
+    LUA_GCSTOP, LUA_GCRESTART, LUA_GCCOLLECT,
+    LUA_GCCOUNT, LUA_GCSTEP, LUA_GCSETPAUSE, LUA_GCSETSTEPMUL,
+    LUA_GCISRUNNING
+];
 const luaB_collectgarbage = function(L) {
-    luaL_checkoption(L, 1, "collect", opts);
-    luaL_optinteger(L, 2, 0);
-    luaL_error(L, to_luastring("lua_gc not implemented"));
+    let o = optsnum[luaL_checkoption(L, 1, "collect", opts)];
+    let ex = luaL_optinteger(L, 2, 0);
+    let res = lua_gc(L, o, ex);
+    if (res == -1)
+        return luaL_error(L, to_luastring("unavailable in current environment"));
+    switch (o) {
+        case LUA_GCCOUNT: {
+            let b = lua_gc(L, LUA_GCCOUNTB, 0);
+            lua_pushnumber(L, res + b/1024);
+            return 1;
+        }
+        case LUA_GCSTEP: case LUA_GCISRUNNING:
+            lua_pushboolean(L, res);
+            return 1;
+        default:
+            lua_pushinteger(L, res);
+            return 1;
+    }
 };
 
 const luaB_type = function(L) {
diff --git a/src/lua.js b/src/lua.js
index 4389c597..f621bec1 100644
--- a/src/lua.js
+++ b/src/lua.js
@@ -13,6 +13,15 @@ module.exports.LUA_ERRGCMM             = defs.thread_status.LUA_ERRGCMM;
 module.exports.LUA_ERRMEM              = defs.thread_status.LUA_ERRMEM;
 module.exports.LUA_ERRRUN              = defs.thread_status.LUA_ERRRUN;
 module.exports.LUA_ERRSYNTAX           = defs.thread_status.LUA_ERRSYNTAX;
+module.exports.LUA_GCCOLLECT           = defs.LUA_GCCOLLECT;
+module.exports.LUA_GCCOUNT             = defs.LUA_GCCOUNT;
+module.exports.LUA_GCCOUNTB            = defs.LUA_GCCOUNTB;
+module.exports.LUA_GCISRUNNING         = defs.LUA_GCISRUNNING;
+module.exports.LUA_GCRESTART           = defs.LUA_GCRESTART;
+module.exports.LUA_GCSETPAUSE          = defs.LUA_GCSETPAUSE;
+module.exports.LUA_GCSETSTEPMUL        = defs.LUA_GCSETSTEPMUL;
+module.exports.LUA_GCSTEP              = defs.LUA_GCSTEP;
+module.exports.LUA_GCSTOP              = defs.LUA_GCSTOP;
 module.exports.LUA_HOOKCALL            = defs.LUA_HOOKCALL;
 module.exports.LUA_HOOKCOUNT           = defs.LUA_HOOKCOUNT;
 module.exports.LUA_HOOKLINE            = defs.LUA_HOOKLINE;