diff --git a/pkgs/development/compilers/ocaml/4.13.nix b/pkgs/development/compilers/ocaml/4.13.nix
new file mode 100644
index 000000000000..dc805f7e61cc
--- /dev/null
+++ b/pkgs/development/compilers/ocaml/4.13.nix
@@ -0,0 +1,9 @@
+import ./generic.nix {
+  major_version = "4";
+  minor_version = "13";
+  patch_version = "0-alpha1";
+  src = fetchTarball {
+    url = "https://caml.inria.fr/pub/distrib/ocaml-4.13/ocaml-4.13.0~alpha1.tar.xz";
+    sha256 = "071k12q8m2w9bcwvfclyc46pwd9r49v6av36fhjdlqq29niyq915";
+  };
+}
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index 8314014e9378..4bc9a592b672 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -1511,6 +1511,8 @@ in let inherit (pkgs) callPackage; in rec
 
   ocamlPackages_4_12 = mkOcamlPackages (callPackage ../development/compilers/ocaml/4.12.nix { });
 
+  ocamlPackages_4_13 = mkOcamlPackages (callPackage ../development/compilers/ocaml/4.13.nix { });
+
   ocamlPackages_latest = ocamlPackages_4_12;
 
   ocamlPackages = ocamlPackages_4_12;