Focused on human capital, economists typically explain about half of the gender earnings gap. For a national sample of MBAs, we account for 82 percent of the gap by incorporating noncognitive skills (for example, confidence and assertiveness) and preferences regarding family, career, and jobs. Those two sources of gender heterogeneity account for a quarter of the "explained" pay gap, with half due to human capital variables and the other quarter due to hours worked and current job characteristics. Female MBAs appear to pay a penalty for "good citizen" behavior (choosing jobs that contribute to society) and characteristics (higher ethical standards). (Contains 10 tables and 41 footnotes.)