Numerous studies have demonstrated the harmful effects of sexual objectification on well-being. However, despite the rapid growth of the #MeToo movement, which has raised public awareness about sexual harassment, there has been much less research investigating the role of sexually objectifying behaviours in motivating people to try to tackle this issue through collective action (e.g., signing petitions, engaging in protests) and the process through which this occurs. Across two studies, we tested whether experiencing sexually objectifying behaviours motivates women to be willing to engage in collective action against sexual objectification via feelings of anger toward women being the target of such actions (i.e., group-based anger). In Studies 1 (n = 127) and 2 (n = 159), female participants rated the extent to which they had been the target of sexually objectifying behaviours, their feelings of group-based anger, and their willingness to engage in collective action against sexual objectification. We found that sexual objectification positively predicted the willingness to engage in collective action and that this relationship was mediated by feelings of group-based anger. This pattern suggests that experiencing numerous instances of sexual objectification is likely to result in women feeling group-based anger and that this anger, in turn, promotes collective action against sexual objectification. Therefore, our research demonstrates one process through which sexual objectification promotes a willingness to engage in collective action.