diff --git a/source/lib/config.ts b/source/lib/config.ts
index 80e1f5f9..d106b422 100644
--- a/source/lib/config.ts
+++ b/source/lib/config.ts
@@ -37,6 +37,7 @@ export default (pkg: {tsd?: RawConfig}, cwd: string): Config => {
 			lib: ['lib.es2017.d.ts'],
 			module: ModuleKind.CommonJS,
 			target: ScriptTarget.ES2017,
+			esModuleInterop: true,
 			...tsConfigCompilerOptions,
 			...packageJsonCompilerOptions,
 			moduleResolution: ModuleResolutionKind.NodeJs,
diff --git a/source/test/fixtures/esm/index.d.ts b/source/test/fixtures/esm/index.d.ts
new file mode 100644
index 00000000..110b2b75
--- /dev/null
+++ b/source/test/fixtures/esm/index.d.ts
@@ -0,0 +1,7 @@
+declare const one: {
+	(foo: string, bar: string): string;
+	(foo: number, bar: number): number;
+	<T extends string>(foo: T, bar: T): string;
+};
+
+export = one;
diff --git a/source/test/fixtures/esm/index.js b/source/test/fixtures/esm/index.js
new file mode 100644
index 00000000..0d28b4c1
--- /dev/null
+++ b/source/test/fixtures/esm/index.js
@@ -0,0 +1,3 @@
+const one = (foo, bar) => foo + bar;
+
+export default one;
diff --git a/source/test/fixtures/esm/index.test-d.ts b/source/test/fixtures/esm/index.test-d.ts
new file mode 100644
index 00000000..67eb5ed0
--- /dev/null
+++ b/source/test/fixtures/esm/index.test-d.ts
@@ -0,0 +1,4 @@
+import {expectType} from '../../../..';
+import one from './index.js';
+
+expectType<string>(one('foo', 'bar'));
diff --git a/source/test/fixtures/esm/package.json b/source/test/fixtures/esm/package.json
new file mode 100644
index 00000000..75bc3f28
--- /dev/null
+++ b/source/test/fixtures/esm/package.json
@@ -0,0 +1,5 @@
+{
+	"name": "foo",
+	"type": "module",
+	"exports": "./index.js"
+}
diff --git a/source/test/test.ts b/source/test/test.ts
index f5afee63..d8d7697f 100644
--- a/source/test/test.ts
+++ b/source/test/test.ts
@@ -103,6 +103,14 @@ test('allow specifying a lib in tsconfig.json', async t => {
 	verify(t, diagnostics, []);
 });
 
+test('add support for esm with esModuleInterop', async t => {
+	const diagnostics = await tsd({
+		cwd: path.join(__dirname, 'fixtures/esm')
+	});
+
+	verify(t, diagnostics, []);
+});
+
 test('a lib option in package.json overrdides a lib option in tsconfig.json', async t => {
 	const diagnostics = await tsd({cwd: path.join(__dirname, 'fixtures/lib-config/lib-from-package-json-overrides-tsconfig-json')});