Adolescents often pursue learning opportunities both in and outside school once they become interested in a topic. In this paper, a learning ecology framework and an associated empirical research agenda are described. This framework highlights the need to better understand how learning outside school relates to learning within schools or other formal organizations, and how learning in school can lead to learning activities outside school. Three portraits of adolescent learners are shared to illustrate different pathways to interest development. Five types of self-initiated learning processes are identified across these case portraits. These include the seeking out of text-based informational sources, the creation of new interactive activity contexts such as projects, the pursuit of structured learning opportunities such as courses, the exploration of media, and the development of mentoring or knowledge-sharing relationships. Implications for theories of human development and ideas for research are discussed.