diff --git a/.github/workflows/pull-request.yml b/.github/workflows/pull-request.yml
index f2bb788e..5491c760 100644
--- a/.github/workflows/pull-request.yml
+++ b/.github/workflows/pull-request.yml
@@ -36,7 +36,7 @@ jobs:
       - name: Setup OCaml
         uses: ocaml/setup-ocaml@v3
         with:
-          ocaml-compiler: 5
+          ocaml-compiler: 5.4.1
           opam-disable-sandboxing: true
           dune-cache: true
         env: