diff --git a/cohttp-async.opam b/cohttp-async.opam
index ca68676306..5a3425a92d 100644
--- a/cohttp-async.opam
+++ b/cohttp-async.opam
@@ -41,6 +41,7 @@ depends: [
   "ounit" {with-test}
   "uri" {>= "2.0.0"}
   "uri-sexp"
+  "ipaddr"
 ]
 build: [
   ["dune" "subst"] {pinned}