diff --git a/docs/specs/devcontainer-features-distribution.md b/docs/specs/devcontainer-features-distribution.md
index 7b4d29b4..9d326959 100644
--- a/docs/specs/devcontainer-features-distribution.md
+++ b/docs/specs/devcontainer-features-distribution.md
@@ -83,6 +83,8 @@ Each features's `devcontainer-feature.json` metadata file is appended into the `
 
 There are several supported ways to distribute Features. Distribution is handled by the implementing packaging tool such as the [Dev Container CLI](https://github.com/devcontainers/cli) or [Dev Container Publish GitHub Action](https://github.com/marketplace/actions/dev-container-publish). See the [quick start repository](https://github.com/devcontainers/feature-template) for a full working example.
 
+> Feature identifiers should be provided lowercase by an author. If not, an implementing packaging tool should normalize the identifier into lowercase for any internal representation.
+
 A user references a distributed feature in a `devcontainer.json` as defined in ['referencing a feature'](./devcontainer-features.md#Referencing-a-feature).
 
 ### OCI Registry
@@ -91,7 +93,7 @@ An OCI registry that implements the [OCI Artifact Distribution Specification](ht
 
 Each packaged feature is pushed to the registry following the naming convention `<registry>/<namespace>/<id>[:version]`, where version is the major, minor, and patch version of the feature, according to the semver specification.
 
-> **Note:** The `namespace` is a unique indentifier for the collection of features.  There are no strict rules for the `namespace`; however, one pattern is to set `namespace` equal to source repository's `<owner>/<repo>`. 
+> **Note:** The `namespace` is a unique indentifier for the collection of features.  There are no strict rules for the `namespace`; however, one pattern is to set `namespace` equal to source repository's `<owner>/<repo>`.  The `namespace` should be lowercase, following [the regex provided in the OCI specification](https://github.com/opencontainers/distribution-spec/blob/main/spec.md#pulling-manifests).
 
 A custom media type `application/vnd.devcontainers` and `application/vnd.devcontainers.layer.v1+tar` are used as demonstrated below.
 
diff --git a/docs/specs/devcontainer-features.md b/docs/specs/devcontainer-features.md
index 7c5d6ecd..af37c6bd 100644
--- a/docs/specs/devcontainer-features.md
+++ b/docs/specs/devcontainer-features.md
@@ -29,7 +29,7 @@ All properties are optional **except for `id`, `version`, and `name`**.
 
 | Property | Type | Description |
 | :--- | :--- | :--- |
-| `id` | string | **Required**: Identifier of the Feature.  Must be unique in the context of the repository where the Feature exists and must match the name of the directory where the `devcontainer-feature.json` resides. |
+| `id` | string | **Required**: Identifier of the Feature.  Must be unique in the context of the repository where the Feature exists and must match the name of the directory where the `devcontainer-feature.json` resides. ID should be provided lowercase. |
 | `version` | string | **Required**: The semantic version of the Feature (e.g: `1.0.0`). |
 | `name` | string | **Required**: A "human-friendly" display name for the Feature. |
 | `description` | string | Description of the Feature. |
@@ -218,6 +218,8 @@ The `id` format specified dictates how a supporting tool will locate and downloa
 | `https://<uri-to-feature-tgz>` | Direct HTTPS URI to a tarball. | `https://github.com/user/repo/releases/devcontainer-feature-go.tgz` |
 | `./<path-to-feature-dir>`| A relative directory(**) to folder containing a devcontainer-feature.json. | `./myGoFeature` |
 
+Feature identifiers should be assumed to be case-insensitive and should be normalized to lowercase.
+
 (*) OCI registry must implement the [OCI Artifact Distribution Specification](https://github.com/opencontainers/distribution-spec).  Some implementors can be [found here](https://oras.land/implementors/).
 
 (**) The provided path is always relative to the folder containing the `devcontainer.json`.  Further requirements are outlined in the [Locally Referenced Addendum](./devcontainer-features-distribution.md#locally-referenced-features)