diff --git a/lib/read-package-json.js b/lib/read-package-json.js
index a8ee072..e0ee9ab 100644
--- a/lib/read-package-json.js
+++ b/lib/read-package-json.js
@@ -6,13 +6,15 @@
  */
 'use strict'
 
-const readPackage = require('read-package-json-fast')
-
 // ------------------------------------------------------------------------------
 // Requirements
 // ------------------------------------------------------------------------------
 
+const fs = require('fs')
 const joinPath = require('path').join
+const parseJson5 = require('json5').parse
+const parseJson = require('json-parse-even-better-errors')
+const normalizePackageData = require('npm-normalize-package-bin')
 
 // ------------------------------------------------------------------------------
 // Public Interface
@@ -24,9 +26,31 @@ const joinPath = require('path').join
  * @returns {object} package.json's information.
  */
 module.exports = function readPackageJson () {
-  const path = joinPath(process.cwd(), 'package.json')
-  return readPackage(path).then(body => ({
-    taskList: Object.keys(body.scripts || {}),
-    packageInfo: { path, body },
-  }))
+  try {
+    let path = joinPath(process.cwd(), 'package.json5')
+    let isJson5 = true
+
+    if (!fs.existsSync(path)) {
+      path = joinPath(process.cwd(), 'package.json')
+      isJson5 = false
+    }
+
+    const rawPkg = fs.readFileSync(path, 'utf8')
+    let body = null
+
+    if (isJson5) {
+      // Read package.json5
+      body = parseJson5(rawPkg)
+    } else {
+      body = parseJson(rawPkg)
+    }
+
+    normalizePackageData(body)
+    return Promise.resolve({
+      taskList: Object.keys(body.scripts || {}),
+      packageInfo: { path, body },
+    })
+  } catch (err) {
+    return Promise.reject(err)
+  }
 }
diff --git a/package.json b/package.json
index 0f8eb90..0222e78 100644
--- a/package.json
+++ b/package.json
@@ -32,10 +32,12 @@
   "dependencies": {
     "ansi-styles": "^6.2.1",
     "cross-spawn": "^7.0.3",
+    "json-parse-even-better-errors": "^4.0.0",
+    "json5": "^2.2.3",
     "memorystream": "^0.3.1",
     "minimatch": "^9.0.0",
+    "npm-normalize-package-bin": "^4.0.0",
     "pidtree": "^0.6.0",
-    "read-package-json-fast": "^4.0.0",
     "shell-quote": "^1.7.3",
     "which": "^5.0.0"
   },
diff --git a/test-workspace/json5/package.json5 b/test-workspace/json5/package.json5
new file mode 100644
index 0000000..ceabac2
--- /dev/null
+++ b/test-workspace/json5/package.json5
@@ -0,0 +1,22 @@
+{
+  /*
+   * Test comment
+   */
+
+  name: "npm-run-all-json5-test",
+  version: "0.0.0",
+  private: true,
+  description: "",
+  engines: {
+    node: ">=4",
+  },
+  config: {
+    test: "OK",
+  },
+  repository: {
+    type: "git",
+    url: "https://github.com/mysticatea/npm-run-all.git",
+  },
+  author: "Toru Nagashima",
+  license: "MIT",
+}
diff --git a/test/json5.js b/test/json5.js
new file mode 100644
index 0000000..4e017c1
--- /dev/null
+++ b/test/json5.js
@@ -0,0 +1,32 @@
+/**
+ * @author Toru Nagashima
+ * @copyright 2016 Toru Nagashima. All rights reserved.
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+const assert = require('assert').strict
+const readPackageJson = require('../lib/read-package-json')
+
+// ------------------------------------------------------------------------------
+// Test
+// ------------------------------------------------------------------------------
+
+describe('[json5]', () => {
+  before(() => process.chdir('test-workspace/json5'))
+  after(() => process.chdir('../..'))
+
+  it('should read package.json5 when available', () =>
+    readPackageJson().then((result) =>
+      assert(result.packageInfo.path.endsWith('/package.json5'))
+    ))
+
+  it('should parse package.json5', () =>
+    readPackageJson().then((result) =>
+      assert(result.packageInfo.body.name === 'npm-run-all-json5-test')
+    ))
+})