Choice is critical for a variety of positive developmental outcomes, including selfesteem, well-being, and intrinsic motivation. The intuition that our actions are freely chosen is also important for our causal reasoning and our moral evaluations of others. In this dissertation, I explore the interplay between young children's concepts of choice and their emerging morality. Chapter 1 reviews current theories of moral development and sets up ideas for future investigations. Chapter 2 explores three related questions: (i) What do children's early concepts of choice look like?; (ii) Do children believe moral and social actions are choices?; and (iii) What are developmental and cultural variations in children's beliefs about moral actions as choices? Chapter 3 focuses on how children make the choice between following moral/social obligations and following their own desires. Chapter 4 directly investigates whether children's ideas of choice influence their emerging prosocial behavior. Finally, Chapter 5 reviews how concepts of choice may be intimately tied to young children's moral cognition and prosocial behavior.