This dissertation examines how academic preparation, finances, and social capital impact postsecondary education enrollment in the United States. The author analyzes data from a longitudinal study to test hypotheses about the effects of social networks, norms, information access, and support systems on college participation. Results support the role of social capital, showing that variables like peer influences, community involvement, and parental engagement positively influence enrollment even after accounting for academic and financial factors. The study aims to inform policies that can increase postsecondary access and reduce inequities.