Psychological processes that hamper activism, such as activist burnout, threaten social change. We suggest that perceived emotional fit (i.e., perceiving to experience similar emotions as other disadvantaged group members) may buffer activist burnout by mitigating the deleterious effects of stressors that are associated with partaking in collective action. We investigated the relation between perceived emotional fit and activist burnout using three-wave longitudinal survey data of Palestinians in the context of the Palestinian–Israeli conflict. We hypothesized that both higher general tendencies to fit emotionally with the ingroup (general perceived emotional fit) and increases over time in perceived emotional fit (change perceived emotional fit) would relate negatively to activist burnout. Supporting our hypotheses, both aspects of emotional fit were associated with lower activist burnout, even when controlling for classical predictors of collective action. This research highlights perceived emotional fit as an additional dimension to the role of emotions for sustainable collective action.