Self-regulation represents a core aspect of human functioning that influences positive development across the life span. This chapter focuses on the action-control model, a key facet of self-regulation during childhood and early adolescence. The authors discuss the development of action-control beliefs, paying particular attention to their relationship to indices of positive development. They then discuss how linking the action-control model with other theories of self-regulation can inform our understanding of self-regulation across the life span. (Contains 1 figure.)