The authors propose a cultural mismatch theory that identifies one source of the social class achievement gap between first-generation and continuing-generation college students. Four studies test the hypothesis that first-generation students underperform because interdependent norms from their mostly working-class backgrounds constitute a mismatch with middle-class independent norms prevalent in universities. First, surveys of university administrators revealed that American universities focus primarily on norms of independence. Second, a longitudinal survey revealed that universities' focus on independence does not match first-generation students' relatively interdependent motives for attending college and that this cultural mismatch is associated with lower grades. Finally, 2 experiments revealed that representing the university culture in terms of independence (i.e., paving one's own paths) rendered academic tasks difficult and, thereby, undermined first-generation students' performance. Conversely, representing the university culture in terms of interdependence (i.e., being part of a community) reduced this sense of difficulty and eliminated the performance gap without adverse consequences for continuing-generation students.