diff --git a/pkgs/tools/filesystems/mtools/default.nix b/pkgs/tools/filesystems/mtools/default.nix
index 949b8c92f84..e7345c639fe 100644
--- a/pkgs/tools/filesystems/mtools/default.nix
+++ b/pkgs/tools/filesystems/mtools/default.nix
@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchurl }:
+{ lib, stdenv, fetchurl, libiconv }:
 
 stdenv.mkDerivation rec {
   pname = "mtools";
@@ -14,6 +14,8 @@ stdenv.mkDerivation rec {
   # fails to find X on darwin
   configureFlags = lib.optional stdenv.isDarwin "--without-x";
 
+  buildInputs = lib.optional stdenv.isDarwin libiconv;
+
   doCheck = true;
 
   meta = with lib; {