diff --git a/README.md b/README.md
index 1903678..40781ca 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,7 @@ What environments should **not** include:
 | [Arduino](envs/arduino)                         | `arduino`             |
 | [cc2538-bsl](envs/cc2538-bsl)                   | `cc2538-bsl`          |
 | [Jruby](envs/jruby)                             | `jruby`               |
+| [Firefox](envs/firefox)                         | `firefox`             |
 | [Github Pages](envs/github-pages)               | `github-pages`        |
 | [Homeassistant](envs/home-assistant)            | `home-assistant`      |
 | [Nannou](envs/nannou)                           | `nannou`              |
diff --git a/default.nix b/default.nix
index 9fc9b1f..c13905a 100644
--- a/default.nix
+++ b/default.nix
@@ -1,6 +1,7 @@
 { pkgs ? import <nixpkgs> {} }: {
   arduino = import ./envs/arduino/shell.nix { inherit pkgs; };
   cc2538-bsl = import ./envs/cc2538-bsl/shell.nix { inherit pkgs; };
+  firefox = import ./envs/firefox/shell.nix { inherit pkgs; };
   github-pages = import ./envs/github-pages/shell.nix { inherit pkgs; };
   home-assistant = import ./envs/home-assistant/shell.nix { inherit pkgs; };
   nannou = import ./envs/nannou/shell.nix { inherit pkgs; };
diff --git a/envs/firefox/shell.nix b/envs/firefox/shell.nix
new file mode 100644
index 0000000..8c0abc6
--- /dev/null
+++ b/envs/firefox/shell.nix
@@ -0,0 +1,32 @@
+{ pkgs ? import <nixpkgs> { }
+, extraPkgs ? [ ]
+}:
+let
+  # Target the LLVM version that rustc is built with for LTO.
+  llvmPackages0 = pkgs.rustc.llvmPackages;
+
+  # Force the use of lld and other llvm tools for LTO
+  llvmPackages = llvmPackages0.override {
+    bootBintoolsNoLibc = null;
+    bootBintools = null;
+  };
+
+  # LTO requires LLVM bintools including ld.lld and llvm-ar.
+  buildStdenv = pkgs.overrideCC llvmPackages.stdenv (llvmPackages.stdenv.cc.override {
+    bintools = pkgs.buildPackages.rustc.llvmPackages.bintools;
+  });
+in
+# Disclaimer: This currently also requies nix-ld (https://github.com/Mic92/nix-ld) to run binaries provided by mozilla.
+buildStdenv.mkDerivation {
+  name = "env";
+  nativeBuildInputs = [
+    pkgs.bashInteractive
+    pkgs.mercurial
+    pkgs.rustc
+    pkgs.cargo
+    pkgs.unzip
+    pkgs.m4
+    pkgs.pkg-config
+  ] ++ pkgs.lib.optional (!pkgs.stdenv.isDarwin) pkgs.libnotify
+  ++ extraPkgs;
+}