diff --git a/pkgs/development/ocaml-modules/cmon/default.nix b/pkgs/development/ocaml-modules/cmon/default.nix
new file mode 100644
index 000000000000..3edc0bb5e226
--- /dev/null
+++ b/pkgs/development/ocaml-modules/cmon/default.nix
@@ -0,0 +1,30 @@
+{
+  lib,
+  fetchurl,
+  buildDunePackage,
+  grenier,
+  pprint,
+}:
+
+buildDunePackage (finalAttrs: {
+  pname = "cmon";
+  version = "0.2";
+
+  src = fetchurl {
+    url = "https://github.com/let-def/cmon/releases/download/v${finalAttrs.version}/cmon-${finalAttrs.version}.tbz";
+    hash = "sha256-lJi5NV27YqyDgUx1i4vBj/buzyzdWJSrSceGGs82grg=";
+  };
+
+  propagatedBuildInputs = [
+    grenier
+    pprint
+  ];
+
+  doCheck = true;
+
+  meta = {
+    description = "A library for printing OCaml values with sharing";
+    license = lib.licenses.mit;
+    homepage = "https://github.com/let-def/cmon";
+  };
+})
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index 4cde20b23f99..cd5d7b34f066 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -269,6 +269,8 @@ let
 
         cmdliner_1 = cmdliner.override { version = "1.3.0"; };
 
+        cmon = callPackage ../development/ocaml-modules/cmon { };
+
         cohttp = callPackage ../development/ocaml-modules/cohttp { };
 
         cohttp_5_3 = cohttp.overrideAttrs (_: {