diff --git a/pkgs/applications/misc/keepass-plugins/keefox/default.nix b/pkgs/applications/misc/keepass-plugins/keefox/default.nix
new file mode 100644
index 000000000000..e32f0b7ca012
--- /dev/null
+++ b/pkgs/applications/misc/keepass-plugins/keefox/default.nix
@@ -0,0 +1,33 @@
+{ stdenv, buildEnv, fetchurl, mono, unzip }:
+
+let
+  version = "1.5.4";
+  drv = stdenv.mkDerivation {
+    name = "keefox-${version}";
+    src = fetchurl {
+      url    = "https://github.com/luckyrat/KeeFox/releases/download/v${version}/${version}.xpi";
+      sha256 = "c7c30770beb0ea32cbdee5311d03a9910fb7772695af3aa655e4ae64cd4d8335";
+    };
+
+    meta = {
+      description = "Keepass plugin for keefox Firefox add-on";
+      homepage    = http://keefox.org;
+      platforms   = with stdenv.lib.platforms; linux;
+      license     = stdenv.lib.licenses.gpl2;
+    };
+
+    buildInputs = [ unzip ];
+
+    pluginFilename = "KeePassRPC.plgx";
+
+    unpackCmd = "unzip $src deps/$pluginFilename ";
+    sourceRoot = "deps";
+
+    installPhase = ''
+      mkdir -p $out/lib/dotnet/keepass/
+      cp $pluginFilename $out/lib/dotnet/keepass/$pluginFilename
+    '';
+  };
+in
+  # Mono is required to compile plugin at runtime, after loading.
+  buildEnv { name = drv.name; paths = [ mono drv ]; }