Despite drastic changes in the American family, a significant minority of Americans marry early. Using data from the National Longitudinal Study of Adolescent Health (N= 14,165), this study evaluates the prevalence and antecedents of early marriage in the United States. The results indicate 25% of women and 16% of men marry before age 23, and early marriage varies widely across a number of characteristics. Individuals who marry earlier are more likely to be from disadvantaged families, from conservative Protestant or Mormon families, to value their religious faith more highly, to have a high-school diploma but a lower educational trajectory, and to cohabit before marriage. Scholars and policymakers interested in marriage should pay adequate attention to understanding and supporting these individuals’ marriages.