diff --git a/pkgs/development/ocaml-modules/janestreet/ppx_sexp_conv-113_33_01.nix b/pkgs/development/ocaml-modules/janestreet/ppx_sexp_conv-113_33_01.nix
new file mode 100644
index 00000000000..d8c9166585e
--- /dev/null
+++ b/pkgs/development/ocaml-modules/janestreet/ppx_sexp_conv-113_33_01.nix
@@ -0,0 +1,21 @@
+{ stdenv, fetchurl, ocaml, findlib, ocamlbuild, opam, topkg
+, sexplib, ppx_deriving, ppx_tools, ppx_type_conv
+}:
+
+stdenv.mkDerivation {
+  name = "ocaml${ocaml.version}-ppx_sexp_conv-133.33.01+4.03";
+  src = fetchurl {
+    url = http://ocaml.janestreet.com/ocaml-core/113.33/files/ppx_sexp_conv-113.33.01+4.03.tar.gz;
+    sha256 = "176pydk5fs8m2md9v8v5b16gra90s4v0ssqq38ghfsbv1faca8d6";
+  };
+
+  buildInputs = [ ocaml findlib ocamlbuild opam ppx_tools ];
+  propagatedBuildInputs = [ sexplib ppx_deriving ppx_type_conv ];
+
+  inherit (topkg) installPhase;
+
+  meta = {
+    license = stdenv.lib.licenses.asl20;
+    inherit (ocaml.meta) platforms;
+  };
+}
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index 09443b93db0..e9567a95859 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -576,7 +576,10 @@ let
 
     ppx_here = callPackage ../development/ocaml-modules/janestreet/ppx-here.nix {};
 
-    ppx_sexp_conv = callPackage ../development/ocaml-modules/janestreet/ppx-sexp-conv.nix {};
+    ppx_sexp_conv =
+      if lib.versionOlder "4.03" ocaml.version
+      then callPackage ../development/ocaml-modules/janestreet/ppx_sexp_conv-113_33_01.nix { }
+      else callPackage ../development/ocaml-modules/janestreet/ppx-sexp-conv.nix {};
 
     ppx_assert = callPackage ../development/ocaml-modules/janestreet/ppx-assert.nix {};