Positive youth development (PYD) is an asset-building approach to youth development research and practice that emphasizes enhancing strengths and developing potential in all youth. With origins in developmental psychology, PYD has increasingly been applied to sport over the past 20 years. In this chapter, we provide an introduction to the area of PYD through sport. We begin by conceptualizing PYD and then provide a brief overview of PYD theories and related research. A case study of a PYD research program is then discussed. Overall, the body of research reviewed in this chapter suggests that sport can be used to promote PYD among different populations and in a range of different contexts. Strong relationships between youth and caring adults (e.g. coaches and parents), as well as strong peer relationships, are important ‘ingredients’ for promoting PYD through sport. Furthermore, opportunities for participants to produce their own experiences, experience leadership, learn life skills, and take initiative are also important principles for promoting PYD. Yet, the delivery of specific PYD approaches can vary; intentional curriculum-based approaches can be effective, but so too can more implicit approaches that focus on creating a ‘PYD climate’ based effective relationships between participants and coaches, peers, and parents.