diff --git a/e2e-test/default/package.json b/e2e-test/default/package.json
index af8d063..f62c942 100644
--- a/e2e-test/default/package.json
+++ b/e2e-test/default/package.json
@@ -3,12 +3,13 @@
 	"description": "Test default config in karmatic.",
 	"private": true,
 	"scripts": {
-		"test:debug": "cross-env NODE_PRESERVE_SYMLINKS_MAIN=1 NODE_PRESERVE_SYMLINKS=1 node ./node_modules/karmatic/dist/cli.js debug"
+		"test:debug": "cross-env NODE_PRESERVE_SYMLINKS_MAIN=1 NODE_PRESERVE_SYMLINKS=1 node ./node_modules/karmatic/dist/cli.js debug --no-webpack",
+		"test": "node ./node_modules/karmatic/dist/cli.js --no-webpack"
 	},
 	"dependencies": {
 		"karmatic": "file:../.."
 	},
 	"devDependencies": {
-		"cross-env": "^7.0.2"
+		"cross-env": "^7.0.3"
 	}
 }
diff --git a/e2e-test/rollup-custom/package.json b/e2e-test/rollup-custom/package.json
index f3f15cb..a4f00fc 100644
--- a/e2e-test/rollup-custom/package.json
+++ b/e2e-test/rollup-custom/package.json
@@ -3,7 +3,8 @@
 	"description": "Test custom rollup config in karmatic",
 	"private": true,
 	"scripts": {
-		"test:debug": "cross-env NODE_PRESERVE_SYMLINKS_MAIN=1 NODE_PRESERVE_SYMLINKS=1 node ./node_modules/karmatic/dist/cli.js debug"
+		"test:debug": "cross-env NODE_PRESERVE_SYMLINKS_MAIN=1 NODE_PRESERVE_SYMLINKS=1 node ./node_modules/karmatic/dist/cli.js debug --no-webpack",
+		"test": "node ./node_modules/karmatic/dist/cli.js --no-webpack"
 	},
 	"dependencies": {
 		"@babel/core": "^7.10.3",
diff --git a/e2e-test/rollup-default/package.json b/e2e-test/rollup-default/package.json
index 57767e5..66b0014 100644
--- a/e2e-test/rollup-default/package.json
+++ b/e2e-test/rollup-default/package.json
@@ -3,7 +3,8 @@
 	"description": "Test default rollup config in karmatic. Mildly complex src implementation to verify coverage works",
 	"private": true,
 	"scripts": {
-		"test:debug": "cross-env NODE_PRESERVE_SYMLINKS_MAIN=1 NODE_PRESERVE_SYMLINKS=1 node ./node_modules/karmatic/dist/cli.js debug"
+		"test:debug": "cross-env NODE_PRESERVE_SYMLINKS_MAIN=1 NODE_PRESERVE_SYMLINKS=1 node ./node_modules/karmatic/dist/cli.js debug --no-webpack",
+		"test": "node ./node_modules/karmatic/dist/cli.js --no-webpack"
 	},
 	"dependencies": {
 		"rollup": "^2.3.0",
diff --git a/src/cli.js b/src/cli.js
index 806939b..5158113 100644
--- a/src/cli.js
+++ b/src/cli.js
@@ -24,6 +24,7 @@ prog
 	.option('--headless', 'Run using Chrome Headless', true)
 	.option('--coverage', 'Report code coverage of tests', true)
 	.option('--downlevel', 'Downlevel syntax to ES5')
+	.option('--webpack', 'Force Webpack usage (--no-webpack disables detection)')
 	.option('--chromeDataDir', 'Save Chrome preferences');
 
 prog
@@ -52,6 +53,7 @@ function run(str, opts, isWatch) {
 	opts.files = toArray(str || opts.files).concat(opts._);
 	const b = opts.browsers || opts.browser;
 	opts.browsers = b ? toArray(b) : null;
+
 	karmatic(opts)
 		.then((output) => {
 			if (output != null) process.stdout.write(output + '\n');
diff --git a/src/configure.js b/src/configure.js
index 3f73c42..397cfe5 100644
--- a/src/configure.js
+++ b/src/configure.js
@@ -12,6 +12,7 @@ import { addRollupConfig } from './rollup';
  * @property {Boolean} [headless=false] - Run in Headless Chrome?
  * @property {Boolean} [watch=false] - Start a continuous test server and retest when files change
  * @property {Boolean} [coverage=false] - Instrument and collect code coverage statistics
+ * @property {Boolean} [webpack] - Override webpack detection (true to force, false to disable)
  * @property {Object} [webpackConfig] - Custom webpack configuration
  * @property {Object} [rollupConfig] - Custom rollup configuration
  * @property {string} [pragma] - JSX pragma to compile JSX with
@@ -218,7 +219,10 @@ export default async function configure(options) {
 		},
 	};
 
-	if (shouldUseWebpack(options)) {
+	if (
+		options.webpack === true ||
+		(options.webpack !== false && shouldUseWebpack(options))
+	) {
 		addWebpackConfig(generatedConfig, pkg, options);
 	} else {
 		await addRollupConfig(generatedConfig, pkg, options);
diff --git a/src/rollup.js b/src/rollup.js
index 8471d27..5957889 100644
--- a/src/rollup.js
+++ b/src/rollup.js
@@ -1,13 +1,17 @@
 import { babelConfig } from './lib/babel';
 import { res, fileExists } from './lib/util';
 
+/** @type {<T>(t: T)=>T extends { default: any } ? T['default'] : T} */
+const getDefault = (mod) => mod.default || mod;
+
 /**
  * @param {import('./configure').Options} options
+ * @returns {import('rollup').RollupOptions}
  */
 function getDefaultConfig(options) {
-	let babel = require('@rollup/plugin-babel').default;
-	let commonjs = require('@rollup/plugin-commonjs');
-	let nodeResolve = require('@rollup/plugin-node-resolve').default;
+	let babel = getDefault(require('@rollup/plugin-babel'));
+	let commonjs = getDefault(require('@rollup/plugin-commonjs'));
+	let nodeResolve = getDefault(require('@rollup/plugin-node-resolve'));
 
 	return {
 		output: {