diff --git a/.changeset/healthy-starfishes-peel.md b/.changeset/healthy-starfishes-peel.md
index 9efbfff80..0e4a55367 100644
--- a/.changeset/healthy-starfishes-peel.md
+++ b/.changeset/healthy-starfishes-peel.md
@@ -1,5 +1,4 @@
 ---
-"@kosko/aggregate-error": major
 "@kosko/cli": major
 "@kosko/common-utils": major
 "@kosko/config": major
diff --git a/.changeset/weak-pumpkins-drum.md b/.changeset/weak-pumpkins-drum.md
new file mode 100644
index 000000000..273f90fd5
--- /dev/null
+++ b/.changeset/weak-pumpkins-drum.md
@@ -0,0 +1,5 @@
+---
+"@kosko/generate": major
+---
+
+Replace the `@kosko/aggregate-error` package with the standard `AggregateError` class.
diff --git a/packages/aggregate-error/CHANGELOG.md b/packages/aggregate-error/CHANGELOG.md
deleted file mode 100644
index 48d58b783..000000000
--- a/packages/aggregate-error/CHANGELOG.md
+++ /dev/null
@@ -1,25 +0,0 @@
-# @kosko/aggregate-error
-
-## 0.3.0
-
-### Minor Changes
-
-- [#118](https://github.com/tommy351/kosko/pull/118) [`9923210`](https://github.com/tommy351/kosko/commit/9923210d7cb465c787966dc55e7755619a921552) Thanks [@tommy351](https://github.com/tommy351)! - Build bundles with Rollup.
-
-- [`69729f8`](https://github.com/tommy351/kosko/commit/69729f869caa8f89c88ff29b8675467e0826000d) Thanks [@tommy351](https://github.com/tommy351)! - Support TypeScript `nodenext` module resolution.
-
-## 0.2.0
-
-### Minor Changes
-
-- [#114](https://github.com/tommy351/kosko/pull/114) [`7744bcd`](https://github.com/tommy351/kosko/commit/7744bcdb86bbfff60350638fe27d89781a6714f7) Thanks [@tommy351](https://github.com/tommy351)! - Set `AggregateError.errors` as an readonly array.
-
-### Patch Changes
-
-- [#114](https://github.com/tommy351/kosko/pull/114) [`7744bcd`](https://github.com/tommy351/kosko/commit/7744bcdb86bbfff60350638fe27d89781a6714f7) Thanks [@tommy351](https://github.com/tommy351)! - Update docs.
-
-## 0.1.0
-
-### Minor Changes
-
-- [#108](https://github.com/tommy351/kosko/pull/108) [`8a6af40`](https://github.com/tommy351/kosko/commit/8a6af40da68fd3a3c8186e3ce008fc06955c4dc4) Thanks [@tommy351](https://github.com/tommy351)! - Implement `AggregateError` polyfill.
diff --git a/packages/aggregate-error/api-extractor.json b/packages/aggregate-error/api-extractor.json
deleted file mode 100644
index 5d9fad992..000000000
--- a/packages/aggregate-error/api-extractor.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-  "$schema": "https://developer.microsoft.com/json-schemas/api-extractor/v7/api-extractor.schema.json",
-  "extends": "../../api-extractor.json",
-  "mainEntryPointFilePath": "<projectFolder>/index.d.ts",
-  "dtsRollup": {
-    "enabled": false
-  }
-}
diff --git a/packages/aggregate-error/index.browser.mjs b/packages/aggregate-error/index.browser.mjs
deleted file mode 100644
index 031d41f5d..000000000
--- a/packages/aggregate-error/index.browser.mjs
+++ /dev/null
@@ -1,2 +0,0 @@
-/* global AggregateError */
-export default AggregateError;
diff --git a/packages/aggregate-error/index.d.mts b/packages/aggregate-error/index.d.mts
deleted file mode 100644
index b2a41529b..000000000
--- a/packages/aggregate-error/index.d.mts
+++ /dev/null
@@ -1 +0,0 @@
-export { AggregateError as default } from "./dist/index.d";
diff --git a/packages/aggregate-error/index.d.ts b/packages/aggregate-error/index.d.ts
deleted file mode 100644
index c286bf52b..000000000
--- a/packages/aggregate-error/index.d.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-/**
- * Polyfill of the standard {@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/AggregateError | AggregateError} class.
- *
- * @packageDocumentation
- */
-
-export { AggregateError as default } from "./dist/index.d";
diff --git a/packages/aggregate-error/index.node.cjs b/packages/aggregate-error/index.node.cjs
deleted file mode 100644
index 3c52224dd..000000000
--- a/packages/aggregate-error/index.node.cjs
+++ /dev/null
@@ -1,7 +0,0 @@
-/* global AggregateError */
-"use strict";
-
-module.exports =
-  typeof AggregateError === "undefined"
-    ? require("./dist/index.node.cjs").AggregateError
-    : AggregateError;
diff --git a/packages/aggregate-error/index.node.mjs b/packages/aggregate-error/index.node.mjs
deleted file mode 100644
index a05053f98..000000000
--- a/packages/aggregate-error/index.node.mjs
+++ /dev/null
@@ -1 +0,0 @@
-export { default } from "./index.node.cjs";
diff --git a/packages/aggregate-error/package.json b/packages/aggregate-error/package.json
deleted file mode 100644
index e83d47625..000000000
--- a/packages/aggregate-error/package.json
+++ /dev/null
@@ -1,57 +0,0 @@
-{
-  "name": "@kosko/aggregate-error",
-  "version": "0.3.0",
-  "description": "AggregateError polyfill.",
-  "homepage": "https://kosko.dev",
-  "repository": "https://github.com/tommy351/kosko/tree/master/packages/aggregate-error",
-  "author": "Tommy Chen <tommy351@gmail.com>",
-  "license": "MIT",
-  "main": "index.node.cjs",
-  "module": "index.node.mjs",
-  "browser": "index.browser.mjs",
-  "types": "index.d.ts",
-  "sideEffects": false,
-  "files": [
-    "dist",
-    "index.d.ts",
-    "index.d.mts",
-    "index.browser.mjs",
-    "index.node.cjs",
-    "index.node.mjs"
-  ],
-  "exports": {
-    "node": {
-      "import": {
-        "types": "./index.d.mts",
-        "default": "./index.node.mjs"
-      },
-      "types": "./index.d.ts",
-      "require": "./index.node.cjs"
-    },
-    "import": {
-      "types": "./index.d.mts",
-      "default": "./index.browser.mjs"
-    },
-    "types": "./index.d.ts",
-    "require": "./index.node.cjs"
-  },
-  "scripts": {
-    "build": "build-scripts"
-  },
-  "keywords": [
-    "kosko"
-  ],
-  "publishConfig": {
-    "access": "public"
-  },
-  "engines": {
-    "node": ">=18"
-  },
-  "devDependencies": {
-    "@kosko/build-scripts": "workspace:^",
-    "@kosko/jest-preset": "workspace:^"
-  },
-  "jest": {
-    "preset": "@kosko/jest-preset"
-  }
-}
diff --git a/packages/aggregate-error/src/AggregateError.ts b/packages/aggregate-error/src/AggregateError.ts
deleted file mode 100644
index f7cc474df..000000000
--- a/packages/aggregate-error/src/AggregateError.ts
+++ /dev/null
@@ -1,29 +0,0 @@
-function defineNonEnumerableProp<T extends object, K extends keyof T>(
-  target: T,
-  key: K,
-  value: T[K]
-) {
-  Object.defineProperty(target, key, { value, enumerable: false });
-}
-
-/**
- * This class implements the standard {@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/AggregateError | AggregateError} class.
- *
- * @public
- */
-export default class AggregateError extends Error {
-  public readonly errors!: readonly unknown[];
-  public readonly cause?: unknown;
-
-  public constructor(
-    errors: Iterable<unknown>,
-    message?: string,
-    options: { cause?: unknown } = {}
-  ) {
-    super(message);
-    defineNonEnumerableProp(this, "errors", [...errors]);
-    defineNonEnumerableProp(this, "cause", options.cause);
-  }
-}
-
-AggregateError.prototype.name = "AggregateError";
diff --git a/packages/aggregate-error/src/__tests__/AggregateError.ts b/packages/aggregate-error/src/__tests__/AggregateError.ts
deleted file mode 100644
index a2e3e151a..000000000
--- a/packages/aggregate-error/src/__tests__/AggregateError.ts
+++ /dev/null
@@ -1,30 +0,0 @@
-import AggregateError from "../AggregateError";
-
-test("only errors is given", () => {
-  const errors = [new Error("first"), new Error("second")];
-  const err = new AggregateError(errors);
-
-  expect(err.name).toEqual("AggregateError");
-  expect(err.errors).toEqual(errors);
-  expect(err.message).toEqual("");
-});
-
-test("when errors is a Set", () => {
-  const errors = new Set([new Error("first"), new Error("second")]);
-  const err = new AggregateError(errors);
-
-  expect(err.errors).toEqual([...errors]);
-});
-
-test("when message is given", () => {
-  const err = new AggregateError([], "foobar");
-
-  expect(err.message).toEqual("foobar");
-});
-
-test("when cause is given", () => {
-  const cause = new Error("err cause");
-  const err = new AggregateError([], "foobar", { cause });
-
-  expect(err.cause).toEqual(cause);
-});
diff --git a/packages/aggregate-error/src/index.ts b/packages/aggregate-error/src/index.ts
deleted file mode 100644
index eab28ce4b..000000000
--- a/packages/aggregate-error/src/index.ts
+++ /dev/null
@@ -1 +0,0 @@
-export { default as AggregateError } from "./AggregateError";
diff --git a/packages/aggregate-error/tsconfig.json b/packages/aggregate-error/tsconfig.json
deleted file mode 100644
index 77cad4f9b..000000000
--- a/packages/aggregate-error/tsconfig.json
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-  "extends": "../../tsconfig.build.json"
-}
diff --git a/packages/cli/package.json b/packages/cli/package.json
index 3c707036b..df7fb13ba 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -51,7 +51,6 @@
     "node": ">=18"
   },
   "dependencies": {
-    "@kosko/aggregate-error": "workspace:^",
     "@kosko/cli-utils": "workspace:^",
     "@kosko/common-utils": "workspace:^",
     "@kosko/config": "workspace:^",
diff --git a/packages/cli/src/commands/generate/__tests__/error.ts b/packages/cli/src/commands/generate/__tests__/error.ts
index 8a70efa2b..dbfe327ee 100644
--- a/packages/cli/src/commands/generate/__tests__/error.ts
+++ b/packages/cli/src/commands/generate/__tests__/error.ts
@@ -1,6 +1,5 @@
 import { handleGenerateError } from "../error";
 import BufferList from "bl";
-import AggregateError from "@kosko/aggregate-error";
 import { GenerateError, ResolveError } from "@kosko/generate";
 import { join, normalize } from "node:path";
 import { CLIError } from "@kosko/cli-utils";
diff --git a/packages/cli/src/commands/generate/error.ts b/packages/cli/src/commands/generate/error.ts
index f0068489a..2cc27d9fa 100644
--- a/packages/cli/src/commands/generate/error.ts
+++ b/packages/cli/src/commands/generate/error.ts
@@ -1,4 +1,3 @@
-import AggregateError from "@kosko/aggregate-error";
 import { GenerateError, ResolveError } from "@kosko/generate";
 import cleanStack from "clean-stack";
 import extractStack from "extract-stack";
diff --git a/packages/generate/package.json b/packages/generate/package.json
index a6882f560..315f80970 100644
--- a/packages/generate/package.json
+++ b/packages/generate/package.json
@@ -43,7 +43,6 @@
     "node": ">=18"
   },
   "dependencies": {
-    "@kosko/aggregate-error": "workspace:^",
     "@kosko/common-utils": "workspace:^",
     "@kosko/log": "workspace:^",
     "@kosko/require": "workspace:^",
diff --git a/packages/generate/src/__tests__/generate.ts b/packages/generate/src/__tests__/generate.ts
index 4bb3b28fc..4ae041da4 100644
--- a/packages/generate/src/__tests__/generate.ts
+++ b/packages/generate/src/__tests__/generate.ts
@@ -4,7 +4,6 @@ import { mkdir, writeFile } from "node:fs/promises";
 import { dirname, join } from "node:path";
 import { GenerateError, ResolveError } from "../error";
 import { makeTempDir, TempDir } from "@kosko/test-utils";
-import AggregateError from "@kosko/aggregate-error";
 import stringify from "fast-safe-stringify";
 
 jest.mock("@kosko/require", () => {
diff --git a/packages/generate/src/__tests__/resolve.ts b/packages/generate/src/__tests__/resolve.ts
index ba6549f11..9824d0b60 100644
--- a/packages/generate/src/__tests__/resolve.ts
+++ b/packages/generate/src/__tests__/resolve.ts
@@ -1,6 +1,5 @@
 /// <reference types="jest-extended" />
 import { getRejectedValue } from "@kosko/test-utils";
-import AggregateError from "@kosko/aggregate-error";
 import assert from "node:assert";
 import { ResolveError } from "../error";
 import { resolve } from "../resolve";
diff --git a/packages/generate/src/error.ts b/packages/generate/src/error.ts
index 43ce84078..de248a440 100644
--- a/packages/generate/src/error.ts
+++ b/packages/generate/src/error.ts
@@ -1,4 +1,3 @@
-import AggregateError from "@kosko/aggregate-error";
 import { isRecord } from "@kosko/common-utils";
 import extractStack from "extract-stack";
 
diff --git a/packages/generate/src/generate.ts b/packages/generate/src/generate.ts
index c44884468..d6f259d8c 100644
--- a/packages/generate/src/generate.ts
+++ b/packages/generate/src/generate.ts
@@ -125,7 +125,7 @@ function validateExtensions(
  * @throws {@link GenerateError}
  * Thrown if an error occurred.
  *
- * @throws {@link @kosko/aggregate-error#AggregateError}
+ * @throws AggregateError
  * Thrown if multiple errors occurred.
  *
  * @public
diff --git a/packages/generate/src/resolve.ts b/packages/generate/src/resolve.ts
index 1087867a8..da8679b37 100644
--- a/packages/generate/src/resolve.ts
+++ b/packages/generate/src/resolve.ts
@@ -121,7 +121,7 @@ export interface ResolveOptions {
  * @throws {@link ResolveError}
  * Thrown if an error occurred.
  *
- * @throws {@link @kosko/aggregate-error#AggregateError}
+ * @throws AggregateError
  * Thrown if multiple errors occurred.
  *
  * @public
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 9ec1373bf..3a8012907 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -228,20 +228,8 @@ importers:
         specifier: ^0.2.3
         version: 0.2.3
 
-  packages/aggregate-error:
-    devDependencies:
-      '@kosko/build-scripts':
-        specifier: workspace:^
-        version: link:../../internal/build-scripts
-      '@kosko/jest-preset':
-        specifier: workspace:^
-        version: link:../../internal/jest-preset
-
   packages/cli:
     dependencies:
-      '@kosko/aggregate-error':
-        specifier: workspace:^
-        version: link:../aggregate-error
       '@kosko/cli-utils':
         specifier: workspace:^
         version: link:../cli-utils
@@ -500,9 +488,6 @@ importers:
 
   packages/generate:
     dependencies:
-      '@kosko/aggregate-error':
-        specifier: workspace:^
-        version: link:../aggregate-error
       '@kosko/common-utils':
         specifier: workspace:^
         version: link:../common-utils