diff --git a/pkgs/build-support/ocaml/topkg.nix b/pkgs/build-support/ocaml/topkg.nix
new file mode 100644
index 000000000000..73be5815e44c
--- /dev/null
+++ b/pkgs/build-support/ocaml/topkg.nix
@@ -0,0 +1,28 @@
+{ lib, stdenv, fetchurl, ocaml, findlib, topkg, ocamlbuild, cmdliner, odoc, b0
+}:
+
+{ pname, version, nativeBuildInputs ? [ ], buildInputs ? [ ], ... }@args:
+
+lib.throwIf (args ? minimalOCamlVersion
+  && lib.versionOlder ocaml.version args.minimalOCamlVersion)
+"${pname}-${version} is not available for OCaml ${ocaml.version}"
+
+stdenv.mkDerivation ({
+
+  dontAddStaticConfigureFlags = true;
+  configurePlatforms = [ ];
+  strictDeps = true;
+  inherit (topkg) buildPhase installPhase;
+
+} // (builtins.removeAttrs args [ "minimalOCamlVersion" ]) // {
+
+  name = "ocaml${ocaml.version}-${pname}-${version}";
+
+  nativeBuildInputs = [ ocaml findlib ocamlbuild topkg ] ++ nativeBuildInputs;
+  buildInputs = [ topkg ] ++ buildInputs;
+
+  meta = (args.meta or { }) // {
+    platforms = args.meta.platforms or ocaml.meta.platforms;
+  };
+
+})
diff --git a/pkgs/development/ocaml-modules/b0/default.nix b/pkgs/development/ocaml-modules/b0/default.nix
new file mode 100644
index 000000000000..e3c21c31e689
--- /dev/null
+++ b/pkgs/development/ocaml-modules/b0/default.nix
@@ -0,0 +1,46 @@
+{ lib, stdenv, fetchurl, ocaml, findlib, topkg, ocamlbuild, cmdliner }:
+
+let
+
+in lib.throwIfNot (lib.versionAtLeast ocaml.version "4.08")
+"b0 is not available for OCaml ${ocaml.version}"
+
+stdenv.mkDerivation rec {
+
+  pname = "ocaml${ocaml.version}-b0";
+  version = "0.0.5";
+
+  src = fetchurl {
+    url = "${meta.homepage}/releases/b0-${version}.tbz";
+    sha256 = "sha256-ty04JQcP4RCme/VQw0ko2IBebWWX5cBU6nRTTeV1I/I=";
+  };
+
+  strictDeps = true;
+
+  nativeBuildInputs = [ ocaml findlib ocamlbuild topkg ];
+  buildInputs = [ topkg cmdliner ];
+
+  inherit (topkg) buildPhase installPhase;
+
+  meta = with lib; {
+    description = "Software construction and deployment kit";
+    longDescription = ''
+      WARNING this package is unstable and work in progress, do not depend on
+      it.
+      B0 describes software construction and deployments using modular and
+      customizable definitions written in OCaml. B0 describes:
+      * Build environments.
+      * Software configuration, build and testing.
+      * Source and binary deployments.
+      * Software life-cycle procedures.
+      B0 also provides the B00 build library which provides abitrary build
+      abstraction with reliable and efficient incremental rebuilds. The B00
+      library can be – and has been – used on its own to devise domain specific
+      build systems.
+    '';
+    homepage = "https://erratique.ch/software/b0";
+    inherit (ocaml.meta) platforms;
+    license = licenses.isc;
+    maintainers = [ maintainers.Julow ];
+  };
+}
diff --git a/pkgs/development/ocaml-modules/odig/default.nix b/pkgs/development/ocaml-modules/odig/default.nix
new file mode 100644
index 000000000000..5ea3730c7ff4
--- /dev/null
+++ b/pkgs/development/ocaml-modules/odig/default.nix
@@ -0,0 +1,25 @@
+{ lib, stdenv, fetchurl, buildTopkgPackage, cmdliner, odoc, b0 }:
+
+buildTopkgPackage rec {
+  pname = "odig";
+  version = "0.0.9";
+
+  src = fetchurl {
+    url = "${meta.homepage}/releases/odig-${version}.tbz";
+    sha256 = "sha256-sYKvGYkxeF5FmrNQdOyMAtlsJqhlmUESi9SkPn/cjM4=";
+  };
+
+  buildInputs = [ cmdliner odoc b0 ];
+
+  meta = with lib; {
+    description = "Lookup documentation of installed OCaml packages";
+    longDescription = ''
+      odig is a command line tool to lookup documentation of installed OCaml
+      packages. It shows package metadata, readmes, change logs, licenses,
+      cross-referenced `odoc` API documentation and manuals.
+    '';
+    homepage = "https://erratique.ch/software/odig";
+    license = licenses.isc;
+    maintainers = [ maintainers.Julow ];
+  };
+}
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 63f4156e3bbe..c01b5f225476 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -16865,6 +16865,8 @@ with pkgs;
     ocamlformat_0_22_4 ocamlformat_0_23_0 ocamlformat_0_24_1 ocamlformat_0_25_1
     ocamlformat_0_26_0;
 
+  inherit (ocamlPackages) odig;
+
   orc = callPackage ../development/compilers/orc { };
 
   orocos-kdl = callPackage ../development/libraries/orocos-kdl { };
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index e6cbbec2da74..71fc1d9a460f 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -60,6 +60,8 @@ let
 
     ### B ###
 
+    b0 = callPackage ../development/ocaml-modules/b0 { };
+
     bap = janeStreet_0_15.bap;
 
     base64 = callPackage ../development/ocaml-modules/base64 { };
@@ -1330,6 +1332,8 @@ let
 
     odate = callPackage ../development/ocaml-modules/odate { };
 
+    odig = callPackage ../development/ocaml-modules/odig { };
+
     odoc = callPackage ../development/ocaml-modules/odoc { };
 
     odoc-parser = callPackage ../development/ocaml-modules/odoc-parser { };
@@ -1888,6 +1892,8 @@ let
 
     buildOasisPackage = callPackage ../build-support/ocaml/oasis.nix { };
 
+    buildTopkgPackage = callPackage ../build-support/ocaml/topkg.nix { };
+
     # Apps from all-packages, to be eventually removed
 
     google-drive-ocamlfuse = callPackage ../applications/networking/google-drive-ocamlfuse { };