Researchers have recently begun to investigate the emotional reactions that lead to consumer boycotts and have suggested moral outrage as a key emotion. This paper extends our understanding of consumer moral outrage in three directions. Firstly, we present a model of moral outrage based on four cognitive appraisals that influence outrage feelings. Secondly, this research shows that feelings of outrage influence protest behavior while at the same time activating moral principles that determine consumers’ ethical judgments and behaviors. Thirdly, this paper demonstrates that moral outrage is stronger when consumers categorize the victims of unethical practices as members of the in-group. This article contributes to research on an important emotional reaction associated with unethical corporate practices and presents critical implications for scholars and managers.