Affluent Americans support more conservative economic policies than the nonaffluent, and government responds disproportionately to these views. Yet little is known about the emergence of these consequential views. We develop, test, and find support for a theory of class cultural norms: These preferences are partly traceable to socialization that occurs on predominantly affluent college campuses, especially those with norms of financial gain, and especially among socially embedded students. The economic views of the student's cohort also matter, in part independently of affluence. We use a large panel data set with a high response rate and more rigorous causal inference strategies than previous socialization studies. The affluent campus effect holds with matching, among students with limited school choice, and in a natural experiment; and it passes placebo tests. College socialization partly explains why affluent Americans support economically conservative policies.