With the proliferation of social activism online, brands face heightened pressure from consumers to publicly address these issues. Yet, the optimal brand response strategy (i.e., whether and how to respond) in these contexts remains unclear. This research investigates consumers' reactions to brand response strategies (e.g., engage vs. not) during social activism and offers potentially effective responses that brands can employ to engage in these issues. By analyzing real-world data collected from Twitter and conducting four randomized experiments, this research discovers that brand relationship type (exchange, communal) affects consumers' brand evaluations in the wake of social activism. Communal (vs. exchange) brands are evaluated less favorably when they do not respond or utilize a low-empathy response. This difference is attenuated when brands employ a high-empathy response. These findings are attributable to consumers' perceptions of whether the brand's response strategy complies with relationship norms during social activism. The effects persist across activism events that vary in their political polarization. This research contributes to the literatures on brand engagement in social activism, brand relationships, and crisis communication. The findings also offer guidance to practitioners on crafting response strategies during social activism and aid activists in securing brand support for societal benefits.