It has become commonplace for consumers to judge companies against social responsibility criteria. Along with such judgments, many consumers are also taking up action, often using the Internet to virally spread their views. Such consumer-led campaigns can put at risk years of investments in branding. For firms understanding what drives consumers to engage in boycotts is key to minimizing exposure to such viral risk. To date, the academic literature has offered disparate and disconnected findings with respect to boycott participation. In this research paper, we review relevant literature, confirm its appropriateness using a series of in-depth interviews, and use our findings to identify key antecedents to consumer participation in boycotts. We then test our proposed model through an empirical study, thus revealing key drivers of consumers' intention to participate in such boycotts. Our results offer insight into factors that companies can manage so as to prevent consumers from participating in boycotts. Copyright © 2013 John Wiley & Sons, Ltd.