Abstract In the face of a challenging climate that is resistant to Diversity, Equity, and Inclusion (DEI) efforts, there is a critical need for a support structure for retaining students, particularly those from historically excluded groups (HEGs), in STEM. The Biology Undergraduate and Master’s Mentorship Program (BUMMP) embodies this commitment to fostering scientific identity, efficacy, and sense of belonging for 1 st generation and historically underserved undergraduate and master’s students at UC San Diego. The mission of BUMMP is to cultivate a sense of belonging, instill confidence, and nurture a strong scientific identity amongst all of its participants. At its core, the three pillars of BUMMP are: 1) mentorship, 2) professional development, and 3) research. Quality mentorship is provided where students receive personal guidance from faculty, graduate students, postdocs, and industry leaders in navigating their career pathways. Complementing mentorship, BUMMP provides paid research opportunities and prioritizes professional development by offering workshops designed to enhance students’ professional skills. These three pillars form the backbone of BUMMP, empowering students from all backgrounds and ensuring their retention and persistence in STEM. So far, we’ve served over 1,350 mentees, collaborated with 809 mentors, and had over 180 mentees actively engaged in BUMMP-sponsored research activities. Overall, BUMMP’s expansive efforts have made a tremendous impact at UC San Diego and will continue to foster a community of future leaders who will be prepared to make meaningful contributions to the scientific community and beyond.