This review article posits that the scarcity of women at the upper levels of organizations is a consequence of gender bias in evaluations. It is proposed that gender stereotypes and the expectations they produce about both what women are like (descriptive) and how they should behave (prescriptive) can result in devaluation of their performance, denial of credit to them for their successes, or their penalization for being competent. The processes giving rise to these outcomes are explored, and the procedures that are likely to encourage them are identified. Because of gender bias and the way in which it influences evaluations in work settings, it is argued that being competent does not ensure that a woman will advance to the same organizational level as an equivalently performing man.