While moral character heavily influences global evaluations of others (Goodwin, Piazza, & Rozin, 2014), its causal effect on perceptions of others’ competence (i.e., one’s knowledge, skills, and abilities) is less clear. We found that people readily use information about another’s morality when judging their competence, despite holding folk intuitions that these domains are independent. Across 6 studies (n = 1,567), including 2 preregistered experiments, participants judged targets who committed hypothetical transgressions (Studies 1 and 3), cheated on lab tasks (Study 2), acted selfishly in economic games (Study 4), and received low morality ratings from coworkers (Study 5 and 6) as less competent than control or moral targets. These findings were specific to morality and were not the result of incidentally manipulating impressions of warmth (Study 4), nor were they fully explained by a general halo effect (Studies 2 and 3). We hypothesized that immoral targets are seen as less competent because their immoral actions led them to be viewed as low in social intelligence. Studies 4 and 5 supported this prediction, demonstrating that social intelligence was a more reliable mediator than perceptions of self-control or general intelligence. An experimental test of this mediation argument found that presenting targets as highly socially intelligent eliminated the negative effect of immoral information on judgments of competence (Study 6). These results suggest that information about a person’s moral character readily influences perceptions of their competence.