diff --git a/gnu/packages/ocaml.scm b/gnu/packages/ocaml.scm
index 0b9ace1759..c5f1eff540 100644
--- a/gnu/packages/ocaml.scm
+++ b/gnu/packages/ocaml.scm
@@ -759,6 +759,7 @@ Knuth’s LR(1) parser construction technique.")
               (uri (git-reference
                      (url "https://github.com/garrigue/lablgtk")
                      (commit "lablgtk2188")))
+              (file-name (git-file-name name version))
               (sha256
                (base32
                 "0gpww8bkwi5cl68kc006970zvzwvq73h1mwrnd239apmwlxc1l8a"))))