This research proposes and tests a new theoretical mechanism to account for a portion of the motherhood penalty in wages and related labor market outcomes. At least a portion of this penalty is attributable to discrimination based on the assumption that mothers are less competent and committed than other types of workers. But what happens when mothers definitively prove their competence and commitment? In this study, we examine whether mothers face discrimination in labor-market-type evaluations even when they provide indisputable evidence that they are competent and committed to paid work. We test the hypothesis that evaluators discriminate against highly successful mothers by viewing them as less warm, less likable, and more interpersonally hostile than otherwise similar workers who are not mothers. The results support this "normative discrimination" hypothesis for female but not male evaluators. The findings have important implications for understanding the nature and persistence of discrimination toward mothers.