Good people typically do good things and bad people typically do bad things. But sometimes actions are ambiguous. How do we make sense of people鈥檚 moral character when acts can be unreliable indicators of inner goodness? Prior research suggests that we rely upon the perceived motivation of an agent. Yet often we don鈥檛 know the reasons behind people鈥檚 acts, making us search for cues of their moral motivation. Building on research on motivation attribution and person perception, we suggest that self-sacrifice, the willingness to incur a personal cost, is a powerful cue that observers use to infer an agent鈥檚 motivation. We hypothesize that an agent will be judged more positively when their action involves self-sacrifice, which is seen as reflecting moral motivation. Five studies (N = 3,132) support this hypothesis across various domains, including views of political policies, assessment of risky military decisions, and resulting monetary decisions.