diff --git a/packages/yojson/yojson.1.5.0/opam b/packages/yojson/yojson.1.5.0/opam
new file mode 100644
index 00000000000..fe695a14af2
--- /dev/null
+++ b/packages/yojson/yojson.1.5.0/opam
@@ -0,0 +1,36 @@
+opam-version: "2.0"
+maintainer: "martin@mjambon.com"
+authors: ["Martin Jambon"]
+homepage: "https://github.com/ocaml-community/yojson"
+bug-reports: "https://github.com/ocaml-community/yojson/issues"
+dev-repo: "git+https://github.com/ocaml-community/yojson.git"
+doc: "https://ocaml-community.github.io/yojson/"
+build: [
+  ["dune" "subst"] {pinned}
+  ["dune" "build" "-p" name "-j" jobs]
+]
+depends: [
+  "ocaml" {>= "4.02.3"}
+  "dune" {build}
+  "cppo" {build}
+  "easy-format"
+  "biniou" {>= "1.2.0"}
+]
+synopsis:
+  "Yojson is an optimized parsing and printing library for the JSON format"
+description: """
+Yojson is an optimized parsing and printing library for the JSON format.
+
+It addresses a few shortcomings of json-wheel including 2x speedup,
+polymorphic variants and optional syntax for tuples and variants.
+
+ydump is a pretty-printing command-line program provided with the
+yojson package.
+
+The program atdgen can be used to derive OCaml-JSON serializers and
+deserializers from type definitions."""
+url {
+  src:
+    "https://github.com/ocaml-community/yojson/releases/download/1.5.0/yojson-1.5.0.tbz"
+  checksum: "md5=d80de1bacdde292af42f7c78b323da7b"
+}