ABSTRACT This paper adapts the agency–beliefs–communion (ABC) model of stereotypes regarding social groups to the context of brand activism. The model predicts that consumers' perceptions of brand agency (A) and brand conservative–progressive beliefs (B) determine brand communion (C). The model also posits that consumers infer a brand's conservative–progressive beliefs from the political orientation of brand activism and that consumers' political identities moderate the directionality of the effect of brand conservative–progressive beliefs on brand communion. Six empirical studies (combined N = 3096) support these propositions. The ABC model clarifies the inconclusive findings of previous studies on the effect of brand activism on consumer reactions. It also explains how brand activism influences consumers' perceptions of brands as either beneficial or harmful to society. Thus, this paper extends the theory of brand activism and consumer perceptions of brands, thereby providing practical implications for the implementation and management of brand activism initiatives.