This prospective longitudinal study examines the antecedents of adolescent mothers' transition into adulthood and their attainment of multiple adult statuses in their early 30s in a nonclinical sample. The distribution, timing, and impact of factors in adolescence (education, employment, marriage, economic status, criminal involvement, and others) are shown relative to their impact on the transition into adulthood and attainment of typical markers of adulthood (employment, economic status, marriage, postsecondary education, and family formation). Descriptive data of demographic variables for adolescent mothers are reported from birth of child at average age 16 through 16 years postpartum at average age 32. Logistic regression results indicate that of all the factors examined in adolescence, on-time graduation from high school or receipt of a GED (by age 19) influenced the attainment of multiple markers of adulthood. Implications for intervention and policy with regard to completion of basic education are discussed.