diff --git a/base64.opam b/base64.opam
index 50efb4f..068d1a8 100644
--- a/base64.opam
+++ b/base64.opam
@@ -5,7 +5,7 @@ authors: [ "Thomas Gazagnaire"
            "Peter Zotov" ]
 license: "ISC"
 homepage: "https://github.com/mirage/ocaml-base64"
-doc: "http://mirage.github.io/ocaml-base64/"
+doc: "https://mirage.github.io/ocaml-base64/"
 bug-reports: "https://github.com/mirage/ocaml-base64/issues"
 dev-repo: "git+https://github.com/mirage/ocaml-base64.git"
 synopsis: "Base64 encoding for OCaml"