diff --git a/jest.config.js b/jest.config.js
index 84c58739ac9..48dba771a53 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -46,7 +46,7 @@ module.exports = {
       ...config,
       displayName: 'JavaScript behaviour tests',
       testMatch: [
-        '**/*.test.js',
+        '**/*.test.{js,mjs}',
 
         // Exclude macro/unit tests
         '!**/(*.)?template.test.{js,mjs}',
@@ -68,7 +68,7 @@ module.exports = {
       testEnvironment: './config/jest/environment/puppeteer.mjs',
       testMatch: [
         '**/all.test.{js,mjs}',
-        '**/components/*/*.test.js',
+        '**/components/*/*.test.{js,mjs}',
 
         // Exclude macro/unit tests
         '!**/(*.)?template.test.{js,mjs}',
diff --git a/src/govuk/all.test.js b/src/govuk/all.test.mjs
similarity index 95%
rename from src/govuk/all.test.js
rename to src/govuk/all.test.mjs
index 71446f49926..3390d507ae4 100644
--- a/src/govuk/all.test.js
+++ b/src/govuk/all.test.mjs
@@ -1,10 +1,10 @@
-const sassdoc = require('sassdoc')
-const slash = require('slash')
+import sassdoc from 'sassdoc'
+import slash from 'slash'
 
-const configPaths = require('../../config/paths.js')
+import configPaths from '../../config/paths.js'
 
-const { renderSass } = require('../../lib/jest-helpers')
-const { goTo, goToExample } = require('../../lib/puppeteer-helpers')
+import { renderSass } from '../../lib/jest-helpers'
+import { goTo, goToExample } from '../../lib/puppeteer-helpers'
 
 describe('GOV.UK Frontend', () => {
   describe('javascript', () => {