Mentoring programs can be effective interventions for improving academic persistence and intrapersonal experiences (e.g., belongingness) for Black students, especially males. However, much of the research has focused on college students rather than Black high school adolescents (Alejandro et al., 2020; Ashktorab et al., 2017; Budge et al., 2020; J. Graham & McClain, 2019; Kennedy & Tuckman, 2013; McKenna et al., 2013). Yet, there is significant research on school belongingness among Black adolescent boys, which indicates belongingness is highly correlated with positive teacher/adult-student relationships (Brooms, 2019; Bulanda & McCrea, 2013; D'hondt et al., 2015; Ellis et al., 2018; Lardier et al., 2019; Pierre et al., 2020). There are many similarities in the literature between general teacher/adult-student relationships and specific mentoring relationships, but there are very few studies evaluating formal school mentoring programs. In addition, there are even fewer studies that focus on Black boys in predominantly White single gender private secondary schools. The following study used mixed methods to evaluate the effectiveness of a formal mentoring program for Black adolescent boys attending a predominantly White single-gender private secondary school. Results of quantitative analyses did not yield any statistically significant differences between pre- and post-mentoring measures of school belongingness of self-efficacy; however, the number of students in quantitative analyses (n = 10) was too small and lacked sufficient power to detect even large magnitude differences. Results of qualitative group interviews with mentees (n = 13) and individual group interviews with mentors (n = 2) revealed several common themes including (a) enhanced community, relationships, and connectivity through shared identities, interests, and (b) shared understanding of racial experiences, marginalization, and consciousness. Limitations and future directions are discussed. [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.]