diff --git a/flambda-backend/tests/backend/vectorizer/.ocamlformat-ignore b/flambda-backend/tests/backend/vectorizer/.ocamlformat-ignore
new file mode 100644
index 0000000000..7ddec40dce
--- /dev/null
+++ b/flambda-backend/tests/backend/vectorizer/.ocamlformat-ignore
@@ -0,0 +1,4 @@
+test_int64_unboxed.ml
+test_float_unboxed.ml
+test_int32_unboxed.ml
+test_float32_unboxed.ml