diff --git a/pkgs/development/ocaml-modules/async_unix/default.nix b/pkgs/development/ocaml-modules/async_unix/default.nix
new file mode 100644
index 00000000000..81fbd6a9918
--- /dev/null
+++ b/pkgs/development/ocaml-modules/async_unix/default.nix
@@ -0,0 +1,27 @@
+{stdenv, buildOcaml, fetchurl, async_kernel,
+ bin_prot, comparelib, core, fieldslib, herelib, pa_ounit,
+ pipebang, pa_test, sexplib}:
+
+buildOcaml rec {
+  name = "async_unix";
+  version = "112.24.00";
+
+  minimumSupportedOcamlVersion = "4.02";
+
+  src = fetchurl {
+    url = "https://github.com/janestreet/async_unix/archive/${version}.tar.gz";
+    sha256 = "d490b1dc42f0987a131fa9695b55f215ad90cdaffbfac35b7f9f88f3834337ab";
+  };
+
+  hasSharedObjects = true;
+  buildInputs = [ pa_ounit ];
+  propagatedBuildInputs = [ async_kernel core bin_prot comparelib
+                            fieldslib herelib pipebang pa_test sexplib ];
+
+   meta = with stdenv.lib; {
+    homepage = https://github.com/janestreet/async_unix;
+    description = "Jane Street Capital's asynchronous execution library (unix)";
+    license = licenses.asl20;
+    maintainers = [ maintainers.ericbmerritt ];
+   };
+}
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index d7886633af9..b6b2c063b68 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -4049,6 +4049,8 @@ let
 
     async_kernel = callPackage ../development/ocaml-modules/async_kernel { };
 
+    async_unix = callPackage ../development/ocaml-modules/async_unix { };
+
     base64 = callPackage ../development/ocaml-modules/base64 { };
 
     bolt = callPackage ../development/ocaml-modules/bolt { };