Although boycotts are increasingly relevant for management decision making, there has been little research of an individual consumer's motivation to boycott. Drawing on the helping behavior and boycott literature, the authors take a cost–benefit approach to the decision to boycott and present a conceptualization of motivations for boycott participation. The authors tested their framework during an actual boycott of a multinational firm that was prompted by factory closings. Consumers who viewed the closures as egregious were more likely to boycott the firm, though only a minority did so. Four factors are found to predict boycott participation: the desire to make a difference, the scope for self-enhancement, counterarguments that inhibit boycotting, and the cost to the boycotter of constrained consumption. Furthermore, self-enhancement and constrained consumption are significant moderators of the relationship between the perceived egregiousness of the firm's actions and boycott participation. The authors also explore the role of perceptions of others’ participation and discuss implications for marketers, nongovernmental organizations, policymakers, and researchers.