According to the theories of reasoned action and planned behavior, the precedent to any human conduct is the intention to display such conduct. One of those precedents is the attitude of people. Our work is framed within this line of research, as it seeks to analyze and explain the main determinants of attitude towards boycott. Thus, we understand that the attitude of consumers towards boycott behavior depends on three fundamental beliefs: perceived legitimacy of the behavior, ethical idealism towards such behavior, and finally, ethical relativism towards boycott behavior. We emphasize legitimacy, since the relevance of legitimacy processes in the business-client relationship lies in the recognition of the validity of actions that allow their subjective recognition and, therefore, differentiate them from the legal nature of the acts. The research is carried out with 371 people and the hypotheses presented are verified through structural equation models. Discussion of the results and its implications contribute to a better understanding of the factors that determine the attitude towards customer boycott by business managers and academics.