The recent literature on ad hominem argument contends that the speaker’s character is sometimes relevant to evaluating what she says. This effort to redeem ad hominems requires an analysis of character that explains why and how character is relevant. I argue that virtue epistemology supplies this analysis. Three sorts of ad hominems that attack the speaker’s intellectual character are legitimate. They attack a speaker’s: (1) possession of reliabilist vices; or (2) possession of responsibilist vices; or (3) failure to perform intellectually virtuous acts. Legitimate ad hominems conclude that we should not believe what a speaker says solely on her say-so.