Afterschool youth development programs (including, arts, leadership, and STEM programs) are significant learning contexts for adolescents. Participation in high-quality programs is related to the acquisition of cognitive, social-emotional, and occupational skills. It is notable that youth in programs report high motivation, markedly higher than in school. Furthermore, motivation increases over time and becomes more self-sustained. This chapter draws on our extensive qualitative interview research with youth and staff to examine questions about how programs-using a project-based learning model-facilitate high and sustained motivation. We find, first, that effective programs create an interpersonal environment of belonging and safety that allows youth to engage in high-functioning relationships, and that projects facilitate motivation because youth experience agency, increasing competency and comradery in their work. Second, although projects periodically confront youth with difficult challenges, which are sometimes overwhelming and can disrupt motivation, youth are typically resilient, and experienced leaders have well-developed strategies for helping youth navigate and learn from these experiences. Third, youth develop sustained motivation because they develop personal connections to program goals and learn techniques to regulate and preempt situations that disrupt motivation. Some youth report learning strategies to help them sustain motivation in the complex, open-ended work of projects.