--- - |2 Abstract Drawing on literatures on social movements and collective action, mentalization, and morality, four studies investigated whether a social movement's use of nonviolence can increase people's willingness to support and join the movement. In a correlational study with a nested design, across 23 movements perceived use of nonviolence predicted participants' willingness to support and join the movement (Study 1, n = 203). This effect was also found experimentally, with Americans supporting nonviolent movements more than violent ones, in hypothetical and real foreign countries (Study 2 and 3, ns = 606 and 373). Study 4 (n = 247) replicated the effects in participants' own country. The effects were transmitted by attribution of mental states to nonviolent movements and subsequent greater perceived morality (Study 2–4). This research demonstrates that nonviolence can benefit social movements in terms of support and mobilization potential, and that these benefits are rooted in perceptions of mental capacity, humanness, and morality. - European Journal of Social Psychology, EarlyView.