Drawing on industrial relations climate theory, in this article the authors hypothesize that abusive supervision results in a negative industrial relations climate which, in turn, is associated with increased employees’ enacted aggression. Moreover, union support was posited as a moderator of both the indirect and direct effects of abusive supervision. Data from 211 union members in Canada supported both processes. Union support moderated the link between industrial relations climate and enacted aggression such that the indirect effect of abusive supervision on aggression was significant at medium and high, but not at low, levels of union support. Moreover, union support moderated the direct relationship between abusive supervision and enacted aggression, such that this relationship was weaker when union support was high. The results suggest that unionization plays an important role in mitigating the effects of abusive supervision and, as such, plays a role in the development of a healthier workplace.