ABSTRACT This study examines how brand activism builds brand trust through two online experiments. Study 1 employed a 2 (crisis: present vs. absent) × 2 (communication strategy: advocacy vs. avoidance) between‐subjects design ( N = 129). Study 2 used a 2 (crisis: present vs. absent) × 2 (crisis‐activism fit: high vs. low) between‐subjects design ( N = 219), testing ethnocentrism as a moderator. Across both experiments, brand trust, attitude toward brand, and word‐of‐mouth (WOM) were measured. Study 1 revealed that in noncrisis contexts, advocacy‐based activism significantly improved brand trust, attitude toward brand, and WOM compared to avoidance strategies. However, during a crisis, activism showed no significant effect on these outcomes. Study 2 indicated that for patriotism‐related crises, high‐fit activism enhanced trust, attitude, and WOM among consumers high in ethnocentrism. No such effect occurred for low‐ethnocentrism consumers. These findings advance theory by highlighting the context‐dependent efficacy of brand activism, the moderating role of consumer ethnocentrism, and the novel concept of crisis‐activism fit in patriotism‐related crises. Managers should avoid activism as a crisis recovery tool unless aligned with consumer values and the crisis context.