According to numerous studies, candidates’ looks predict voters’ choices—a finding that raises concerns about voter competence and about the quality of elected officials. This potentially worrisome finding, however, is observational and therefore vulnerable to alternative explanations. To better test the appearance effect, we conducted two experiments. Just before primary and general elections for various offices, we randomly assigned voters to receive ballots with and without candidate photos. Simply showing voters these pictures increased the vote for appearance-advantaged candidates. Experimental evidence therefore supports the view that candidates’ looks could influence some voters. In general elections, we find that high-knowledge voters appear immune to this influence, while low-knowledge voters use appearance as a low-information heuristic. In primaries, however, candidate appearance influences even high-knowledge and strongly partisan voters.