diff --git a/pkgs/development/ocaml-modules/rock/default.nix b/pkgs/development/ocaml-modules/rock/default.nix
new file mode 100644
index 00000000000..ae484e937b8
--- /dev/null
+++ b/pkgs/development/ocaml-modules/rock/default.nix
@@ -0,0 +1,35 @@
+{ lib, fetchurl, buildDunePackage
+, bigstringaf
+, hmap
+, httpaf
+, lwt
+, sexplib0
+}:
+
+buildDunePackage rec {
+  pname = "rock";
+  version = "0.20.0";
+  minimalOCamlVersion = "4.08";
+  duneVersion = "3";
+
+  src = fetchurl {
+    url = "https://github.com/rgrinberg/opium/releases/download/${version}/opium-${version}.tbz";
+    hash = "sha256-MmuRhm3pC69TX4t9Sy/yPjnZUuVzwEs8E/EFS1n/L7Y=";
+  };
+
+  propagatedBuildInputs = [
+    bigstringaf
+    hmap
+    httpaf
+    lwt
+    sexplib0
+  ];
+
+  meta = {
+    description = "Minimalist framework to build extensible HTTP servers and clients";
+    homepage = "https://github.com/rgrinberg/opium";
+    license = lib.licenses.mit;
+    maintainers = [ lib.maintainers.vbgl ];
+  };
+
+}
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index 88500959422..6a8ce3aec37 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -1204,6 +1204,8 @@ let
 
     result = callPackage ../development/ocaml-modules/ocaml-result { };
 
+    rock = callPackage ../development/ocaml-modules/rock { };
+
     samplerate = callPackage ../development/ocaml-modules/samplerate { };
 
     secp256k1 = callPackage ../development/ocaml-modules/secp256k1 {