 <p>You can't access data asset files in the same way you access a random file using <code>NSBundle.pathForResource</code>. Since they can only be defined within <code>Assets.xcassets</code>, you need to initialize a <code>NSDataAsset</code> instance in order to access the contents of it: </p> <pre><code>let asset = NSDataAsset(name: "Colors", bundle: NSBundle.mainBundle()) let json = try? NSJSONSerialization.JSONObjectWithData(asset!.data, options: NSJSONReadingOptions.AllowFragments) print(json) </code></pre> <p>Please note that <code>NSDataAsset</code> class was introduced as of iOS 9.0 &amp; macOS 10.11.</p> <p><strong>Swift3 version:</strong></p> <pre><code>let asset = NSDataAsset(name: "Colors", bundle: Bundle.main) let json = try? JSONSerialization.jsonObject(with: asset!.data, options: JSONSerialization.ReadingOptions.allowFragments) print(json) </code></pre> <p>Also, NSDataAsset is surprisingly located in UIKit/AppKit so don't forget to import the relevant framework in your code:</p> <pre><code>#if os(iOS) import UIKit #elseif os(OSX) import AppKit #endif </code></pre>