<p>This study investigates the impact of transdisciplinary collaboration within higher education institutions on the sustainability of digital libraries, focusing on community engagement as a mediating factor. Transdisciplinary collaboration refers to the coordinated integration of diverse disciplinary perspectives and expertise among librarians, faculty, technical staff, and administrators to manage and sustain digital library services. The study has used structural equation modeling on data collected from multiple higher education institutions of Delhi-NCR region from India. The study examines how such collaboration influences community engagement—the active participation of users in co-creating and improving digital library resources—and, in turn, digital library sustainability. Results indicate that while transdisciplinary collaboration does not directly affect sustainability significantly, it positively influences community engagement, which fully mediates the relationship with sustainability. These findings underscore the critical role of user participation in translating collaborative efforts into sustainable digital library outcomes. The study contributes theoretical insights and practical guidance for fostering resilient, user-centered digital library ecosystems in higher education.</p>