Underrepresented minority (URM) students are at elevated risks for dropping out of school and lower academic achievement. Factors that contribute to such challenges begin early (e.g., childhood poverty) and compound throughout one's lifetime. Nonetheless, research that explores challenges faced by URMs typically focus on contemporary issues (e.g., college GPA) and ignore earlier factors. Using data from the High School Longitudinal Study of 2009, this longitudinal study explored the links between social capital during high school and college success among African American Black and Hispanic Latino respondents. This study examined whether social capital from parents, siblings, teachers, and peers during high school (Time 1) were directly linked to degree attainment and persistence during college (Time 2), or if intermediary variables (i.e., personal assets) account for this relation. Four research guided this study: (a) Does social capital during high school directly predict college success? (b) Do different sources of social capital during high school predict future orientation during high school and college involvement? (c) Do future orientation and college involvement mediate the relationship between social capital and college success? (d) What types of college involvement predict college success? Results suggest that social capital from parents, siblings, and peers during high school uniquely operate to contribute to college success. Parental social capital in high school directly predicted higher likelihood of later degree attainment and persistence in college; whereas sibling and peer social capital during high school were indirectly linked to college success through perceptions of differential treatment of instructors based on race and use of different services on campus respectively. No evidence of direct or indirect effects were found for social capital from teachers during high school. For intermediary variables, sense of future possible selves, perceptions of differential treatment by race, and use of campus services were significantly linked to higher likelihood of college success. Together, findings provide evidence of the importance of social capital prior to college in later academic success and persistence of URMs in college. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]