The increasing abundance of personal data related to health and wellness presents new opportunities for discovery and insight and can help individuals learn from their own experiences, as well as from experiences of others. These trends inspired active research in machine learning and data mining; they also present new opportunities for research in Human-Computer Interaction. There remain many open questions as to how to design interactive systems that leverage new streams of personal and social data and new data science capabilities to promote learning and decision-making in health. In my research, I investigate these questions in the context of self-management of chronic diseases such as type 2 diabetes. In this talk I will discuss several ongoing research initiatives that strive to facilitate reflection and learning, provide in-the-moment decision support, and guide individuals’ actions.