diff --git a/docs/Configuration.md b/docs/Configuration.md
index ad7c3d76d79f..09ef73b2437b 100644
--- a/docs/Configuration.md
+++ b/docs/Configuration.md
@@ -425,7 +425,15 @@ Activates notifications for test results.
 Default: `undefined`
 
 A preset that is used as a base for Jest's configuration. A preset should point
-to an npm module that exports a `jest-preset.json` module on its top level.
+to an npm module that exports a `jest-preset.json` or `jest-preset.js` module at its top level.
+
+Presets may also be relative filesystem paths.
+
+```json
+{
+  "preset": "./node_modules/foo-bar/jest-preset.js"
+}
+```
 
 ### `projects` [array<string>]
 
diff --git a/packages/jest-config/src/__tests__/normalize.test.js b/packages/jest-config/src/__tests__/normalize.test.js
index 19cbf8d62eb9..3145a8f16a12 100644
--- a/packages/jest-config/src/__tests__/normalize.test.js
+++ b/packages/jest-config/src/__tests__/normalize.test.js
@@ -859,6 +859,24 @@ describe('preset', () => {
       }),
       {virtual: true},
     );
+    jest.mock(
+      '/node_modules/with-json-ext/jest-preset.json',
+      () => ({
+        moduleNameMapper: {
+          json: true,
+        },
+      }),
+      {virtual: true},
+    );
+    jest.mock(
+      '/node_modules/with-js-ext/jest-preset.js',
+      () => ({
+        moduleNameMapper: {
+          js: true,
+        },
+      }),
+      {virtual: true},
+    );
   });
 
   afterEach(() => {
@@ -905,6 +923,30 @@ describe('preset', () => {
     }).not.toThrow();
   });
 
+  test('supports .json preset files', () => {
+    const {options} = normalize(
+      {
+        preset: 'with-json-ext',
+        rootDir: '/root/path/foo',
+      },
+      {},
+    );
+
+    expect(options.moduleNameMapper).toEqual([['json', true]]);
+  });
+
+  test('supports .js preset files', () => {
+    const {options} = normalize(
+      {
+        preset: 'with-js-ext',
+        rootDir: '/root/path/foo',
+      },
+      {},
+    );
+
+    expect(options.moduleNameMapper).toEqual([['js', true]]);
+  });
+
   test('merges with options', () => {
     const {options} = normalize(
       {
diff --git a/packages/jest-config/src/normalize.js b/packages/jest-config/src/normalize.js
index e7fba4434f83..5e475fcfe03a 100644
--- a/packages/jest-config/src/normalize.js
+++ b/packages/jest-config/src/normalize.js
@@ -39,8 +39,8 @@ import DEPRECATED_CONFIG from './deprecated';
 import setFromArgv from './set_from_argv';
 import VALID_CONFIG from './valid_config';
 const ERROR = `${BULLET}Validation Error`;
-const JSON_EXTENSION = '.json';
-const PRESET_NAME = 'jest-preset' + JSON_EXTENSION;
+const PRESET_EXTENSIONS = ['.json', '.js'];
+const PRESET_NAME = 'jest-preset';
 
 const createConfigError = message =>
   new ValidationError(ERROR, message, DOCUMENTATION_NOTE);
@@ -52,14 +52,35 @@ const setupPreset = (
   let preset;
   const presetPath = _replaceRootDirInPath(options.rootDir, optionsPreset);
   const presetModule = Resolver.findNodeModule(
-    presetPath.endsWith(JSON_EXTENSION)
+    presetPath.charAt(0) === '.'
       ? presetPath
       : path.join(presetPath, PRESET_NAME),
     {
       basedir: options.rootDir,
+      extensions: PRESET_EXTENSIONS,
     },
   );
 
+  // const foundModule = PRESET_EXTENSIONS.some(ext => {
+  // const presetModule = Resolver.findNodeModule(
+  //   presetPath.charAt(0) === '.' || presetPath.endsWith(ext)
+  //     ? presetPath
+  //     : path.join(presetPath, PRESET_NAME + ext),
+  //   {
+  //     basedir: options.rootDir,
+  //   },
+  // );
+  //
+  //   try {
+  //     // $FlowFixMe
+  //     preset = (require(presetModule): InitialOptions);
+  //   } catch (error) {
+  //     return false;
+  //   }
+  //
+  //   return true;
+  // });
+
   try {
     // $FlowFixMe
     preset = (require(presetModule): InitialOptions);