This qualitative, longitudinal study explores how student members’ sense of belonging changed over time in a Networked Improvement Community (NIC). Co-authored by researchers and student participants, this study uses the “students as partners” framework and four constructs of belonging (motivation, competencies, opportunities, and perceptions) to examine how sense of belonging manifested and developed for five student NIC members across their first and final semesters of participation in the NIC. Retrospective analysis of journal entries and interview data collected over two years revealed: student motivations shifted from individual goals to a collective investment in the NIC’s systemic improvement goals; students developed competencies in leadership, data-informed decision-making, and equity based on their lived experiences; and intentional NIC structures supported a shift in the student members’ opportunities for belonging from relationship-building and anonymous decision-making to taking on more responsibilities in NIC initiatives. As a result, student perceptions evolved from uncertainty about their roles to having a strong sense of agency, influence, and community within the department. The findings from this study offer evidence that intentionally structured NICs can function as spaces where motivations, competencies, opportunities, and perceptions grow together and position student members as contributors to inclusive systemic change in undergraduate STEM education.