diff --git a/.eslintrc.json b/.eslintrc.json
index 2522061174..c6e793864c 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -61,7 +61,8 @@
     "jsdoc/tag-lines": 0,
 
     "node/no-unsupported-features/es-syntax": 0,
-    "node/no-missing-import": [2, { "tryExtensions": [".js", ".json", ".ts"] }]
+    "node/file-extension-in-import": ["error", "always"],
+    "node/no-missing-import": 0
   },
   "settings": {
     "jsdoc": {
diff --git a/benchmark/benchmark.ts b/benchmark/benchmark.ts
index 45dcbc77df..178625eaba 100755
--- a/benchmark/benchmark.ts
+++ b/benchmark/benchmark.ts
@@ -1,5 +1,5 @@
-import Suites from './suite';
-import type { Cheerio } from '../src/cheerio';
+import Suites from './suite'; // eslint-disable-line node/file-extension-in-import
+import type { Cheerio } from '../src/cheerio.js';
 import type { Element } from 'domhandler';
 
 const suites = new Suites();
diff --git a/benchmark/suite.ts b/benchmark/suite.ts
index a93fb624c1..8a8db68caf 100644
--- a/benchmark/suite.ts
+++ b/benchmark/suite.ts
@@ -5,7 +5,7 @@ import { Suite, Event } from 'benchmark';
 // @ts-expect-error `jsdom` types currently collide with `parse5` types.
 import { JSDOM } from 'jsdom';
 import { Script } from 'vm';
-import cheerio from '../src';
+import cheerio from '../lib/index.js';
 
 const documentDir = path.join(__dirname, 'documents');
 const jQuerySrc = fs.readFileSync(
diff --git a/package.json b/package.json
index bd0dee1e1c..3fd433463a 100644
--- a/package.json
+++ b/package.json
@@ -26,6 +26,17 @@
   "homepage": "https://cheerio.js.org/",
   "main": "lib/index.js",
   "types": "lib/index.d.ts",
+  "module": "lib/esm/index.js",
+  "exports": {
+    ".": {
+      "require": "./lib/index.js",
+      "import": "./lib/esm/index.js"
+    },
+    "./lib/slim": {
+      "require": "./lib/slim.js",
+      "import": "./lib/esm/slim.js"
+    }
+  },
   "files": [
     "lib"
   ],
@@ -80,10 +91,12 @@
     "format:prettier": "npm run format:prettier:raw -- --write",
     "format:prettier:raw": "prettier \"**/*.{{m,c,}js,ts,md,json,yml}\" --ignore-path .gitignore",
     "build:docs": "typedoc --hideGenerator src/index.ts",
-    "benchmark": "ts-node benchmark/benchmark.ts --regex \"^(?!.*highmem)\"",
+    "benchmark": "npm run build:cjs && ts-node benchmark/benchmark.ts --regex \"^(?!.*highmem)\"",
     "update-sponsors": "ts-node scripts/fetch-sponsors.ts",
     "bench": "npm run benchmark",
-    "build": "tsc",
+    "build": "npm run build:cjs && npm run build:esm",
+    "build:cjs": "tsc --sourceRoot https://github.com/raw/cheeriojs/cheerio/$(git rev-parse HEAD)/src/",
+    "build:esm": "npm run build:cjs -- --module esnext --target es2019 --outDir lib/esm && echo '{\"type\":\"module\"}' > lib/esm/package.json",
     "prepublishOnly": "npm run build",
     "prepare": "husky install"
   },
@@ -107,6 +120,9 @@
     "testPathIgnorePatterns": [
       "/__fixtures__/"
     ],
-    "coverageProvider": "v8"
+    "coverageProvider": "v8",
+    "moduleNameMapper": {
+      "^(.*)\\.js$": "$1"
+    }
   }
 }
diff --git a/src/__tests__/deprecated.spec.ts b/src/__tests__/deprecated.spec.ts
index bdf47944de..42d5bff9b4 100644
--- a/src/__tests__/deprecated.spec.ts
+++ b/src/__tests__/deprecated.spec.ts
@@ -3,7 +3,7 @@
  * removed in the next major release of Cheerio, but their stability should be
  * maintained until that time.
  */
-import * as fixtures from '../__fixtures__/fixtures';
+import * as fixtures from '../__fixtures__/fixtures.js';
 import cheerio from '..';
 
 describe('deprecated APIs', () => {
diff --git a/src/__tests__/xml.spec.ts b/src/__tests__/xml.spec.ts
index 7cd3374001..84a1135ddd 100644
--- a/src/__tests__/xml.spec.ts
+++ b/src/__tests__/xml.spec.ts
@@ -1,5 +1,5 @@
 import cheerio from '..';
-import type { CheerioOptions } from '../options';
+import type { CheerioOptions } from '../options.js';
 
 function xml(str: string, options?: CheerioOptions) {
   options = { xml: true, ...options };
diff --git a/src/api/attributes.spec.ts b/src/api/attributes.spec.ts
index ec60bb3ddc..fccdf90265 100644
--- a/src/api/attributes.spec.ts
+++ b/src/api/attributes.spec.ts
@@ -1,5 +1,5 @@
 import cheerio from '..';
-import type { Cheerio } from '../cheerio';
+import type { Cheerio } from '../cheerio.js';
 import type { Element } from 'domhandler';
 import {
   script,
@@ -9,7 +9,7 @@ import {
   chocolates,
   inputs,
   mixedText,
-} from '../__fixtures__/fixtures';
+} from '../__fixtures__/fixtures.js';
 
 describe('$(...)', () => {
   let $: typeof cheerio;
diff --git a/src/api/attributes.ts b/src/api/attributes.ts
index a4b70c21d0..f78327b238 100644
--- a/src/api/attributes.ts
+++ b/src/api/attributes.ts
@@ -4,10 +4,10 @@
  * @module cheerio/attributes
  */
 
-import { text } from '../static';
-import { isTag, domEach, camelCase, cssCase } from '../utils';
+import { text } from '../static.js';
+import { isTag, domEach, camelCase, cssCase } from '../utils.js';
 import type { AnyNode, Element } from 'domhandler';
-import type { Cheerio } from '../cheerio';
+import type { Cheerio } from '../cheerio.js';
 import { innerText, textContent } from 'domutils';
 const hasOwn = Object.prototype.hasOwnProperty;
 const rspace = /\s+/;
diff --git a/src/api/css.spec.ts b/src/api/css.spec.ts
index 25adad0fb2..0eccb70c81 100644
--- a/src/api/css.spec.ts
+++ b/src/api/css.spec.ts
@@ -1,7 +1,7 @@
 import cheerio from '..';
-import type { Cheerio } from '../cheerio';
+import type { Cheerio } from '../cheerio.js';
 import type { Element } from 'domhandler';
-import { mixedText } from '../__fixtures__/fixtures';
+import { mixedText } from '../__fixtures__/fixtures.js';
 
 describe('$(...)', () => {
   describe('.css', () => {
diff --git a/src/api/css.ts b/src/api/css.ts
index 2a63767823..10dd344f72 100644
--- a/src/api/css.ts
+++ b/src/api/css.ts
@@ -1,6 +1,6 @@
-import { domEach, isTag } from '../utils';
+import { domEach, isTag } from '../utils.js';
 import type { Element, AnyNode } from 'domhandler';
-import type { Cheerio } from '../cheerio';
+import type { Cheerio } from '../cheerio.js';
 
 /**
  * Get the value of a style property for the first element in the set of matched elements.
diff --git a/src/api/forms.spec.ts b/src/api/forms.spec.ts
index c6ca427829..082ff2582d 100644
--- a/src/api/forms.spec.ts
+++ b/src/api/forms.spec.ts
@@ -1,6 +1,6 @@
 import cheerio from '../../src';
-import type { CheerioAPI } from '../load';
-import { forms } from '../__fixtures__/fixtures';
+import type { CheerioAPI } from '../load.js';
+import { forms } from '../__fixtures__/fixtures.js';
 
 describe('$(...)', () => {
   let $: CheerioAPI;
diff --git a/src/api/forms.ts b/src/api/forms.ts
index cc0df8a9e5..6116cdd77e 100644
--- a/src/api/forms.ts
+++ b/src/api/forms.ts
@@ -1,6 +1,6 @@
 import type { AnyNode } from 'domhandler';
-import type { Cheerio } from '../cheerio';
-import { isTag } from '../utils';
+import type { Cheerio } from '../cheerio.js';
+import { isTag } from '../utils.js';
 
 /*
  * https://github.com/jquery/jquery/blob/2.1.3/src/manipulation/var/rcheckableType.js
diff --git a/src/api/manipulation.spec.ts b/src/api/manipulation.spec.ts
index d382ef09f7..34bbf911f0 100644
--- a/src/api/manipulation.spec.ts
+++ b/src/api/manipulation.spec.ts
@@ -1,6 +1,6 @@
 import { load } from '../../src';
 import type { CheerioAPI, Cheerio } from '..';
-import { fruits, divcontainers, mixedText } from '../__fixtures__/fixtures';
+import { fruits, divcontainers, mixedText } from '../__fixtures__/fixtures.js';
 import type { AnyNode, Element } from 'domhandler';
 
 describe('$(...)', () => {
diff --git a/src/api/manipulation.ts b/src/api/manipulation.ts
index 8799fe07b7..d79735f3a8 100644
--- a/src/api/manipulation.ts
+++ b/src/api/manipulation.ts
@@ -5,12 +5,12 @@
  */
 
 import { ParentNode, AnyNode, Element, Text, hasChildren } from 'domhandler';
-import { update as updateDOM } from '../parse';
-import { text as staticText } from '../static';
-import { domEach, cloneDom, isTag, isHtml, isCheerio } from '../utils';
+import { update as updateDOM } from '../parse.js';
+import { text as staticText } from '../static.js';
+import { domEach, cloneDom, isTag, isHtml, isCheerio } from '../utils.js';
 import { removeElement } from 'domutils';
-import type { Cheerio } from '../cheerio';
-import type { BasicAcceptedElems, AcceptedElems } from '../types';
+import type { Cheerio } from '../cheerio.js';
+import type { BasicAcceptedElems, AcceptedElems } from '../types.js';
 
 /**
  * Create an array of nodes, recursing into arrays and parsing strings if necessary.
diff --git a/src/api/traversing.spec.ts b/src/api/traversing.spec.ts
index 7c6ebe370a..94893bfedb 100644
--- a/src/api/traversing.spec.ts
+++ b/src/api/traversing.spec.ts
@@ -1,6 +1,6 @@
 import cheerio from '../../src';
-import { Cheerio } from '../cheerio';
-import type { CheerioAPI } from '../load';
+import { Cheerio } from '../cheerio.js';
+import type { CheerioAPI } from '../load.js';
 import { AnyNode, Element, Text, isText } from 'domhandler';
 import {
   food,
@@ -11,7 +11,7 @@ import {
   forms,
   mixedText,
   vegetables,
-} from '../__fixtures__/fixtures';
+} from '../__fixtures__/fixtures.js';
 
 function getText(el: Cheerio<Element>) {
   if (!el.length) return undefined;
diff --git a/src/api/traversing.ts b/src/api/traversing.ts
index 40470172e3..08f3a542aa 100644
--- a/src/api/traversing.ts
+++ b/src/api/traversing.ts
@@ -11,10 +11,10 @@ import {
   isDocument,
   Document,
 } from 'domhandler';
-import type { Cheerio } from '../cheerio';
+import type { Cheerio } from '../cheerio.js';
 import * as select from 'cheerio-select';
-import { domEach, isTag, isCheerio } from '../utils';
-import { contains } from '../static';
+import { domEach, isTag, isCheerio } from '../utils.js';
+import { contains } from '../static.js';
 import {
   getChildren,
   getSiblings,
@@ -22,7 +22,7 @@ import {
   prevElementSibling,
   uniqueSort,
 } from 'domutils';
-import type { FilterFunction, AcceptedFilters } from '../types';
+import type { FilterFunction, AcceptedFilters } from '../types.js';
 const reSiblingSelector = /^\s*[~+]/;
 
 /**
diff --git a/src/cheerio.spec.ts b/src/cheerio.spec.ts
index c93d44bd28..29e005ea84 100644
--- a/src/cheerio.spec.ts
+++ b/src/cheerio.spec.ts
@@ -1,10 +1,10 @@
 import { parseDOM } from 'htmlparser2';
 import cheerio from '.';
-import * as utils from './utils';
-import { fruits, food, noscript } from './__fixtures__/fixtures';
-import type { Cheerio } from './cheerio';
+import * as utils from './utils.js';
+import { fruits, food, noscript } from './__fixtures__/fixtures.js';
+import type { Cheerio } from './cheerio.js';
 import type { Element } from 'domhandler';
-import type { CheerioOptions } from './options';
+import type { CheerioOptions } from './options.js';
 
 declare module '.' {
   interface Cheerio<T> {
diff --git a/src/cheerio.ts b/src/cheerio.ts
index f7fbacdf20..e3824e0cf6 100644
--- a/src/cheerio.ts
+++ b/src/cheerio.ts
@@ -1,12 +1,12 @@
-import type { InternalOptions } from './options';
+import type { InternalOptions } from './options.js';
 import type { AnyNode, Document, ParentNode } from 'domhandler';
-import type { BasicAcceptedElems } from './types';
+import type { BasicAcceptedElems } from './types.js';
 
-import * as Attributes from './api/attributes';
-import * as Traversing from './api/traversing';
-import * as Manipulation from './api/manipulation';
-import * as Css from './api/css';
-import * as Forms from './api/forms';
+import * as Attributes from './api/attributes.js';
+import * as Traversing from './api/traversing.js';
+import * as Manipulation from './api/manipulation.js';
+import * as Css from './api/css.js';
+import * as Forms from './api/forms.js';
 
 type AttributesType = typeof Attributes;
 type TraversingType = typeof Traversing;
diff --git a/src/index.spec.ts b/src/index.spec.ts
index ef755e40d3..0ad8c2fddc 100644
--- a/src/index.spec.ts
+++ b/src/index.spec.ts
@@ -1,5 +1,5 @@
-import * as cheerio from './index';
-import * as statics from './static';
+import * as cheerio from './index.js';
+import * as statics from './static.js';
 
 describe('index', () => {
   it('should export all static methods', () => {
diff --git a/src/index.ts b/src/index.ts
index 09c4ec5c2d..94b8f2d49e 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -3,19 +3,19 @@
  *
  * @category Cheerio
  */
-export type { Cheerio } from './cheerio';
+export type { Cheerio } from './cheerio.js';
 
 /**
  * Types used in signatures of Cheerio methods.
  *
  * @category Cheerio
  */
-export * from './types';
+export * from './types.js';
 export type {
   CheerioOptions,
   HTMLParser2Options,
   Parse5Options,
-} from './options';
+} from './options.js';
 /**
  * Re-exporting all of the node types.
  *
@@ -23,10 +23,10 @@ export type {
  */
 export type { Node, NodeWithChildren, Element, Document } from 'domhandler';
 
-export type { CheerioAPI } from './load';
-import { getLoad } from './load';
-import { getParse } from './parse';
-import { renderWithParse5, parseWithParse5 } from './parsers/parse5-adapter';
+export type { CheerioAPI } from './load.js';
+import { getLoad } from './load.js';
+import { getParse } from './parse.js';
+import { renderWithParse5, parseWithParse5 } from './parsers/parse5-adapter.js';
 import renderWithHtmlparser2 from 'dom-serializer';
 import { parseDocument as parseWithHtmlparser2 } from 'htmlparser2';
 
@@ -83,9 +83,9 @@ import { filters, pseudos, aliases } from 'cheerio-select';
  */
 export const select = { filters, pseudos, aliases };
 
-export * from './static';
+export * from './static.js';
 
-import * as staticMethods from './static';
+import * as staticMethods from './static.js';
 
 /**
  * In order to promote consistency with the jQuery library, users are encouraged
diff --git a/src/load.ts b/src/load.ts
index 2038f222a7..a1161f904d 100644
--- a/src/load.ts
+++ b/src/load.ts
@@ -3,12 +3,12 @@ import {
   InternalOptions,
   default as defaultOptions,
   flatten as flattenOptions,
-} from './options';
-import * as staticMethods from './static';
-import { Cheerio } from './cheerio';
-import { isHtml, isCheerio } from './utils';
+} from './options.js';
+import * as staticMethods from './static.js';
+import { Cheerio } from './cheerio.js';
+import { isHtml, isCheerio } from './utils.js';
 import type { AnyNode, Document, Element, ParentNode } from 'domhandler';
-import type { SelectorType, BasicAcceptedElems } from './types';
+import type { SelectorType, BasicAcceptedElems } from './types.js';
 
 type StaticType = typeof staticMethods;
 
diff --git a/src/parse.spec.ts b/src/parse.spec.ts
index 2931758a2f..4b29d384fd 100644
--- a/src/parse.spec.ts
+++ b/src/parse.spec.ts
@@ -1,9 +1,9 @@
 import type { Document, Element } from 'domhandler';
-import { getParse } from './parse';
-import defaultOpts from './options';
+import { getParse } from './parse.js';
+import defaultOpts from './options.js';
 
 import { parseDocument as parseWithHtmlparser2 } from 'htmlparser2';
-import { parseWithParse5 } from './parsers/parse5-adapter';
+import { parseWithParse5 } from './parsers/parse5-adapter.js';
 
 const parse = getParse((content, options, isDocument, context) =>
   options.xmlMode || options._useHtmlParser2
diff --git a/src/parse.ts b/src/parse.ts
index 6ade82560e..c4dda11067 100644
--- a/src/parse.ts
+++ b/src/parse.ts
@@ -5,7 +5,7 @@ import {
   ParentNode,
   isDocument as checkIsDocument,
 } from 'domhandler';
-import type { InternalOptions } from './options';
+import type { InternalOptions } from './options.js';
 
 /*
  * Parser
diff --git a/src/parsers/parse5-adapter.ts b/src/parsers/parse5-adapter.ts
index d59f36d0d9..9d802fadee 100644
--- a/src/parsers/parse5-adapter.ts
+++ b/src/parsers/parse5-adapter.ts
@@ -1,7 +1,7 @@
 import { AnyNode, Document, isDocument, ParentNode } from 'domhandler';
 import { parse as parseDocument, parseFragment, serializeOuter } from 'parse5';
 import { adapter as htmlparser2Adapter } from 'parse5-htmlparser2-tree-adapter';
-import type { InternalOptions } from '../options';
+import type { InternalOptions } from '../options.js';
 
 export function parseWithParse5(
   content: string,
diff --git a/src/slim.ts b/src/slim.ts
index 1dfe839cfa..7bdd090308 100644
--- a/src/slim.ts
+++ b/src/slim.ts
@@ -16,10 +16,10 @@ export type {
  *
  * @category Cheerio
  */
-export * from './types';
+export * from './types.js';
 
-import { getLoad } from './load';
-import { getParse } from './parse';
+import { getLoad } from './load.js';
+import { getParse } from './parse.js';
 import render from 'dom-serializer';
 import { parseDocument } from 'htmlparser2';
 
diff --git a/src/static.spec.ts b/src/static.spec.ts
index 9b7f7f7c16..9f5aff2a72 100644
--- a/src/static.spec.ts
+++ b/src/static.spec.ts
@@ -1,4 +1,4 @@
-import * as fixtures from './__fixtures__/fixtures';
+import * as fixtures from './__fixtures__/fixtures.js';
 import cheerio, { CheerioAPI } from '.';
 
 describe('cheerio', () => {
diff --git a/src/static.ts b/src/static.ts
index cba34410c6..463383bd82 100644
--- a/src/static.ts
+++ b/src/static.ts
@@ -1,4 +1,4 @@
-import type { BasicAcceptedElems } from './types';
+import type { BasicAcceptedElems } from './types.js';
 import type { CheerioAPI, Cheerio } from '.';
 import { AnyNode, Document, isText, hasChildren } from 'domhandler';
 import {
@@ -6,7 +6,7 @@ import {
   CheerioOptions,
   default as defaultOptions,
   flatten as flattenOptions,
-} from './options';
+} from './options.js';
 import { ElementType } from 'htmlparser2';
 
 /**
diff --git a/src/types.ts b/src/types.ts
index 7cc41c6275..99b5b9efd8 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -40,7 +40,7 @@ export type SelectorType =
   | `${SelectorSpecial}${AlphaNumeric}${string}`
   | `${AlphaNumeric}${string}`;
 
-import type { Cheerio } from './cheerio';
+import type { Cheerio } from './cheerio.js';
 import type { AnyNode } from 'domhandler';
 
 /** Elements that can be passed to manipulation methods. */
diff --git a/src/utils.ts b/src/utils.ts
index 88f65930ee..3114a11370 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,5 +1,5 @@
 import { type AnyNode, cloneNode, Document } from 'domhandler';
-import type { Cheerio } from './cheerio';
+import type { Cheerio } from './cheerio.js';
 
 /**
  * Check if the DOM element is a tag.