Although negative out-group beliefs typically foster individuals' motivation for collective action, we propose that such beliefs may diminish this motivation when people believe that this out-group cannot change in its very essence. Specifically, we tested the idea that believing in the malleability of immoral out-groups (i.e., targets of collective action) should increase collective action tendencies through group efficacy beliefs. Study 1 revealed that the more strongly participants believed that immoral out-groups could change as a function of contextual influences, the stronger their collective action tendencies were due to increased group efficacy. In Study 2, we experimentally replicated these findings using a manipulation of individu...