diff --git a/package.json b/package.json
index 987cd29..0b6c5a1 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@glideapps/ts-necessities",
-    "version": "2.2.3",
+    "version": "2.2.4",
     "description": "Small utilities to make life with TypeScript easier",
     "main": "dist/index.js",
     "types": "dist/index.d.ts",
diff --git a/src/index.ts b/src/index.ts
index 5e736e8..14392d8 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -93,6 +93,8 @@ export type Writable<T> = { -readonly [P in keyof T]: T[P] };
 
 export type DeepWritable<T> = { -readonly [P in keyof T]: DeepWritable<T[P]> };
 
+export type DeepReadonly<T> = { readonly [P in keyof T]: DeepReadonly<T[P]> };
+
 /**
  * If `x` is undefined, return `undefined`.  Otherwise, return `f(x)`.
  */