Abstract This study examined the influence of Vice Chancellors’ instructional leadership practices and organizational climate on lecturers’ collective efficacy in Lagos State-owned universities. Using a descriptive survey design, data were collected from 359 academic staff across three universities through structured questionnaires measuring leadership practices, organizational climate, and collective efficacy. Correlation analyses revealed significant positive relationships between instructional leadership and collective efficacy (r = 0.248), leadership and organizational climate (r = 0.791), and organizational climate and collective efficacy (r = 0.208). Multiple regression analysis indicated that both instructional leadership practices (β = 0.359) and organizational climate (β = 0.651) significantly predict lecturers’ collective efficacy, explaining 46.9% of its variance. Findings highlighted the critical role of effective leadership and a supportive organizational climate in promoting a collaborative academic environment that enhances lecturers’ shared belief in their collective ability to achieve institutional goals. The study recommended that Vice Chancellors prioritize goal-setting, communication, and professional development while promoting an inclusive climate characterized by trust and collaboration to strengthen faculty collective efficacy and institutional success. This research fills a gap in Nigerian higher education literature by empirically linking leadership and climate to collective efficacy, offering a framework for improving academic staff collaboration and performance. Keywords: Instructional Leadership Practices, Organizational Climate, Collective Efficacy, Lecturers, Higher Education