diff --git a/dune-project b/dune-project
index 04dbc4f4..fcc937c9 100644
--- a/dune-project
+++ b/dune-project
@@ -73,7 +73,7 @@
     :with-test
     (>= 0.19)))
   (hmap :with-test)
-  lwt
+  (lwt (and (>= 5.0) (< 6.0)))
   base-unix
   (trace :with-test)
   (trace-tef :with-test)
diff --git a/moonpool-lwt.opam b/moonpool-lwt.opam
index d29944ad..af4c8dc5 100644
--- a/moonpool-lwt.opam
+++ b/moonpool-lwt.opam
@@ -13,7 +13,7 @@ depends: [
   "ocaml" {>= "5.0"}
   "qcheck-core" {with-test & >= "0.19"}
   "hmap" {with-test}
-  "lwt"
+  "lwt" {>= "5.0" & < "6.0"}
   "base-unix"
   "trace" {with-test}
   "trace-tef" {with-test}