diff --git a/image-index.md b/image-index.md
index ab8732e62..ab3dc4e9c 100644
--- a/image-index.md
+++ b/image-index.md
@@ -109,6 +109,7 @@ When the variant of the CPU is not listed in the table, values are implementatio
 ```json,title=Image%20Index&mediatype=application/vnd.oci.image.index.v1%2Bjson
 {
   "schemaVersion": 2,
+  "mediaType": "application/vnd.oci.image.index.v1+json",
   "manifests": [
     {
       "mediaType": "application/vnd.oci.image.manifest.v1+json",
diff --git a/manifest.md b/manifest.md
index 9cb833afd..29b8b1af7 100644
--- a/manifest.md
+++ b/manifest.md
@@ -78,6 +78,7 @@ Unlike the [image index](image-index.md), which contains information about a set
 ```json,title=Manifest&mediatype=application/vnd.oci.image.manifest.v1%2Bjson
 {
   "schemaVersion": 2,
+  "mediaType": "application/vnd.oci.image.manifest.v1+json",
   "config": {
     "mediaType": "application/vnd.oci.image.config.v1+json",
     "size": 7023,