Amidst rising economic inequality and mounting evidence of its pernicious social effects, what motivates opposition to inequality? Five studies (n = 34,442) show that attributing poverty to situational forces is associated with greater concern about inequality, preference for egalitarian policies and inequality-reducing behaviour. In Study 1, situational attributions for poverty were associated with reduced support for inequality across 34 countries. Study 2 replicated these findings with a nationally representative sample of Americans. Three experiments then tested whether situational attributions for poverty are malleable and motivate egalitarianism. Bolstering situational attributions for poverty through a writing exercise (Study 3) and a computer-based poverty simulation (Studies 4a and b) increased egalitarian action and reduced support for inequality immediately (Studies 3 and 4b), 1 d later and 155 d post-intervention (Study 4b). Causal attributions for poverty offer one accessible means of shaping inequality-reducing attitudes and actions. Situational attributions may be a potent psychological lever for lessening societal inequality.