diff --git a/package.json b/package.json
index ae06083..45ca335 100644
--- a/package.json
+++ b/package.json
@@ -62,7 +62,7 @@
     "unbuild": "^2.0.0",
     "vite": "^4.2.1",
     "vitest": "^0.29.8",
-    "zod": "^3.21.4"
+    "zod": "^3.22.4"
   },
   "simple-git-hooks": {
     "pre-commit": "yarn lint-staged"
diff --git a/src/MockGenerator.ts b/src/MockGenerator.ts
index 7bcf81d..85795f0 100644
--- a/src/MockGenerator.ts
+++ b/src/MockGenerator.ts
@@ -32,6 +32,7 @@ import PipelineGenerator from './generators/PipelineGenerator';
 import BrandedGenerator from './generators/BrandedGenerator';
 import FunctionGenerator from './generators/FunctionGenerator';
 import LazyGenerator from './generators/LazyGenerator';
+import ReadonlyGenerator from './generators/ReadonlyGenerator';
 import { DepthLimitError } from './errors/DepthLimitError';
 
 const _schemasCache = new WeakMap<z.ZodTypeAny, any>();
@@ -78,6 +79,7 @@ export default class MockGenerator<T extends z.ZodTypeAny> {
       ZodBranded: BrandedGenerator,
       ZodFunction: FunctionGenerator,
       ZodLazy: LazyGenerator,
+      ZodReadonly: ReadonlyGenerator,
     };
 
     if (this.schema._def.typeName in generatorMap) {
diff --git a/src/generators/ReadonlyGenerator.ts b/src/generators/ReadonlyGenerator.ts
new file mode 100644
index 0000000..26c10ac
--- /dev/null
+++ b/src/generators/ReadonlyGenerator.ts
@@ -0,0 +1,10 @@
+import type { ZodReadonly, ZodTypeAny } from 'zod';
+import MockGenerator from '../MockGenerator';
+import type BaseGenerator from './BaseGenerator';
+
+export default class ReadonlyGenerator<T extends ZodTypeAny, U extends ZodReadonly<T>> implements BaseGenerator<U> {
+  public generate(schema: U) {
+    const mockGenerator = new MockGenerator(schema._def.innerType);
+    return Object.freeze(mockGenerator.generate());
+  }
+}
diff --git a/tests/readonly.test.ts b/tests/readonly.test.ts
new file mode 100644
index 0000000..eb24e09
--- /dev/null
+++ b/tests/readonly.test.ts
@@ -0,0 +1,22 @@
+import { describe, test } from 'vitest';
+import { z } from 'zod';
+import { expect } from './utils/expect';
+
+describe('Readonly', () => {
+  test('base', () => {
+    const object = z.object({ foo: z.string(), bar: z.number() }).readonly();
+    expect(object);
+
+    const array = z.array(z.string()).readonly();
+    expect(array);
+
+    const string = z.string().readonly();
+    expect(string);
+
+    const number = z.number().readonly();
+    expect(number);
+
+    const boolean = z.boolean().readonly();
+    expect(boolean);
+  });
+});
diff --git a/yarn.lock b/yarn.lock
index f82919a..3f097bb 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4385,7 +4385,7 @@ yocto-queue@^1.0.0:
   resolved "https://registry.yarnpkg.com/yocto-queue/-/yocto-queue-1.0.0.tgz#7f816433fb2cbc511ec8bf7d263c3b58a1a3c251"
   integrity sha512-9bnSc/HEW2uRy67wc+T8UwauLuPJVn28jb+GtJY16iiKWyvmYJRXVT4UamsAEGQfPohgr2q4Tq0sQbQlxTfi1g==
 
-zod@^3.21.4:
-  version "3.21.4"
-  resolved "https://registry.yarnpkg.com/zod/-/zod-3.21.4.tgz#10882231d992519f0a10b5dd58a38c9dabbb64db"
-  integrity sha512-m46AKbrzKVzOzs/DZgVnG5H55N1sv1M8qZU3A8RIKbs3mrACDNeIOeilDymVb2HdmP8uwshOCF4uJ8uM9rCqJw==
+zod@^3.22.4:
+  version "3.22.4"
+  resolved "https://registry.yarnpkg.com/zod/-/zod-3.22.4.tgz#f31c3a9386f61b1f228af56faa9255e845cf3fff"
+  integrity sha512-iC+8Io04lddc+mVqQ9AZ7OQ2MrUKGN+oIQyq1vemgt46jwCwLfhq7/pwnBnNXXXZb8VTVLKwp9EDkx+ryxIWmg==