diff --git a/pkgs/development/tools/ocaml/ocp-build/default.nix b/pkgs/development/tools/ocaml/ocp-build/default.nix
index de26536eb1c5..33f9a123b744 100644
--- a/pkgs/development/tools/ocaml/ocp-build/default.nix
+++ b/pkgs/development/tools/ocaml/ocp-build/default.nix
@@ -1,5 +1,8 @@
 { lib, stdenv, fetchFromGitHub, fetchpatch, ocaml, findlib, ncurses, cmdliner_1_0, re }:
 
+lib.throwIf (lib.versionAtLeast ocaml.version "5.0")
+  "ocp-build is not available for OCaml ${ocaml.version}"
+
 stdenv.mkDerivation rec {
   pname = "ocaml${ocaml.version}-ocp-build";
   version = "1.99.21";