A Google Certified Android Developer is someone who has passed Google's certification exam demonstrating their proficiency in Android development. This exam covers a range of topics including Java programming language, Android SDK tools and APIs, Android app architecture, testing and debugging, user interface and user experience, and Google Play Store integration. Obtaining this certification indicates that the developer has a thorough understanding of Android development and is capable of creating high-quality Android apps that are up to the standards set forth by Google. This certification provides credibility to the developer's skills and can make them more marketable to potential employers or clients.