diff --git a/pkgs/development/ocaml-modules/ocaml-protoc-plugin/default.nix b/pkgs/development/ocaml-modules/ocaml-protoc-plugin/default.nix
index 067b61212ace..ed9b299320d8 100644
--- a/pkgs/development/ocaml-modules/ocaml-protoc-plugin/default.nix
+++ b/pkgs/development/ocaml-modules/ocaml-protoc-plugin/default.nix
@@ -49,5 +49,9 @@ buildDunePackage rec {
       and de-serialization function from a .proto file.
     '';
     maintainers = [ lib.maintainers.GirardR1006 ];
+    # Broken with Dune 3.15.1:
+    #   Error: Dependency cycle between:
+    #      %{read:config/support_proto3_optional.conf} at test/dune:16
+    broken = true;
   };
 }
diff --git a/pkgs/development/tools/ocaml/dune/3.nix b/pkgs/development/tools/ocaml/dune/3.nix
index 42d13fcbb320..7e1d1d630599 100644
--- a/pkgs/development/tools/ocaml/dune/3.nix
+++ b/pkgs/development/tools/ocaml/dune/3.nix
@@ -6,11 +6,11 @@ else
 
 stdenv.mkDerivation rec {
   pname = "dune";
-  version = "3.15.0";
+  version = "3.15.1";
 
   src = fetchurl {
     url = "https://github.com/ocaml/dune/releases/download/${version}/dune-${version}.tbz";
-    hash = "sha256-tcPRD29gSL+vVvxPCULVY4G1WvQofK+CUUh9TE55INc=";
+    hash = "sha256-tbeKSgLU3QiUI02/cYv/R3/Nheff3/6OzgC5oM89VHs=";
   };
 
   nativeBuildInputs = [ ocaml findlib ];