Research on the mechanisms that reproduce social class advantages in the United States focuses primarily on formal schooling and pays less attention to social class discrimination in labor markets. We conducted a résumé audit study to examine the effect of social class signals on entry into large U.S. law firms. We sent applications from fictitious students at selective but non-elite law schools to 316 law firm offices in 14 cities, randomly assigning signals of social class background and gender to otherwise identical résumés. Higher-class male applicants received significantly more callbacks than did higher-class women, lower-class women, and lower-class men. A survey experiment and interviews with lawyers at large firms suggest that, relative to lower-class applicants, higher-class candidates are seen as better fits with the elite culture and clientele of large law firms. But, although higher-class men receive a corresponding overall boost in evaluations, higher-class women do not, because they face a competing, negative stereotype that portrays them as less committed to full-time, intensive careers. This commitment penalty faced by higher-class women offsets class-based advantages these applicants may receive in evaluations. Consequently, signals of higher-class origin provide an advantage for men but not for women in this elite labor market.