Software applications (or apps) are distributed very differently these days than how they were once distributed - through centralized market places (which has changed the way developers interact with users, the way software is released, and consumed). These app markets, which are now standard for mobile apps, are getting popular now for desktop apps, games, and even open source apps. Such markets make it easier for app developers to release their new apps and update their existing apps. It also makes it easier for users to search, compare and download new apps and keep their existing apps up to date. Additionally, the app markets provide useful guidance to developers so that end users have the best quality apps. Finally, the market is public facing and has unique data like user comments, release notes, app popularity, besides just the app itself. Hence, app markets can be mined and the resulting data analyzed by researchers and analytics companies. Therefore, in this workshop (happening in conjunction with FSE 2016), we seek to bring together researchers and practitioners to discuss research challenges, ideas, initiatives and results that leverages such app market data to answer pertinent software engineering questions.