diff --git a/dune-project b/dune-project
index a4e6c6cb6a402d0861d527e71ba976ba72d47c32..8c48bfb2d917fa6d5ff1416d53a5a5f27de42bd7 100644
--- a/dune-project
+++ b/dune-project
@@ -20,4 +20,5 @@
   (clangml (>= 4.1.0))
   (dolog (>= 4.0.0))
   (traverse (>= 0.2.0))
-  (refl (>= 0.1.0))))
+  (refl (>= 0.1.0))
+  (odoc (and :with-doc (>= 1.5.1)))))