"Success Boston Coaching" is a coaching intervention for students who are traditionally underrepresented in college to help them transition from high school to college and progress in college. Students are paired with a dedicated coach starting as early as the spring of their senior year of high school and receive coaching through their first two years in college. As Boston's citywide college completion initiative, Success Boston partners with existing nonprofit organizations focused on coaching and mentoring to deliver these one-on-one coaching services. Nonprofit coaching partners may also provide students with other direct services such as tutoring and career readiness support, and financial support that includes scholarships, transportation subsidies, and funding for school-related materials and supplies. This What Works Clearinghouse (WWC) report, part of the WWC's Supporting Postsecondary Success topic area, explores the effects of "Success Boston Coaching" on progressing in college and academic achievement. The WWC identified seven studies of "Success Boston Coaching." Two of these studies meet WWC standards. The evidence presented in this report is from studies of the impact of "Success Boston Coaching" on high school and postsecondary students-- including Asian, African-American, Hispanic, and White students--in a variety of school settings, including urban and suburban areas. [For the Intervention Brief, see ED608189. For the Intervention Snapshot, see ED608190.]