The mHealth Compendium series has expanded the body of knowledge and increased access to the most current information on mobile technology solutions for health (mHealth). Each volume links users to key tools and resources, and serves as a significant resource for mHealth information. The mHealth Compendium Special Edition 2016: Reaching Scale presents ten in-depth profiles of programs previously featured in the mHealth Compendium that have grown in scale over time. These case studies include details of the process, challenges, and lessons learned in growing an mHealth program.