This chapter addresses several central issues in the study of revenge during childhood and adolescence, focusing specifically on moral evaluations of retaliation and retributive justice. We begin by distinguishing among relevant concepts and consider their respective moral status by discussing their moral-philosophical foundations. Next, we summarize and critique classic developmental psychology research on children’s reasoning about retaliation, focusing on Piaget’s (1932) early work but also addressing Kohlberg’s (1981) account when appropriate. This is followed by a discussion of social-cognitive domain theory (SCDT), a constructivist developmental perspective that we assert is better able than earlier psychological approaches to address the ambiguities of provocation, retaliation, and revenge. Consistent with recent trends in SCDT research, we also consider individual differences in children’s evaluations and responses to provocation, focusing on research investigating the social and psychological correlates of retaliatory aggression. Finally, the chapter concludes with a review of key findings and suggestions for future research.