diff --git a/cohttp-eio.opam b/cohttp-eio.opam
index 9420a1f8a..ab89f0956 100644
--- a/cohttp-eio.opam
+++ b/cohttp-eio.opam
@@ -21,7 +21,7 @@ bug-reports: "https://github.com/mirage/ocaml-cohttp/issues"
 depends: [
   "dune" {>= "3.0"}
   "base-domains"
-  "eio" {>= "0.10"}
+  "eio" {>= "0.10" & < "0.12"}
   "eio_main" {with-test}
   "mdx" {with-test}
   "uri" {with-test}
diff --git a/dune-project b/dune-project
index ec0e8d34b..db6150c45 100644
--- a/dune-project
+++ b/dune-project
@@ -357,7 +357,9 @@ should also be fine under Windows too.
  (depends
   base-domains
   (eio
-   (>= 0.10))
+   (and
+    (>= 0.10)
+    (< 0.12)))
   (eio_main :with-test)
   (mdx :with-test)
   (uri :with-test)