This study examines the influence of diamond open access (DOA) publishing on research engagement among library professionals in India. Using a quantitative approach, data were collected through a structured online survey administered to 106 library professionals who had published in DOA journals. The findings reveal a strong consensus on the benefits of DOA, particularly its capacity to ensure equitable access to scholarly content by eliminating article processing charges (APCs) and enhancing the visibility and impact of research outputs. Respondents emphasized DOA’s potential to promote inclusivity, especially for researchers in under-resourced settings, and its role in fostering collaboration and diversity in scholarly publishing. However, the study also identifies critical challenges that hinder the widespread adoption of DOA. These include limited journal availability, concerns about journal quality and prestige, and the uncertain sustainability of the fee-free model. Despite these concerns, statistical analyses indicate that library professionals regard DOA as a viable and impactful alternative to gold open access, especially in terms of long-term benefits to scholarly communication. The study highlights the evolving role of library professionals as not just information custodians but also active contributors and advocates in the open access movement. It recommends institutional recognition and support for library professionals as strategic stewards of DOA publishing initiatives. The findings underscore the need for sustained advocacy, infrastructure development, and collaborative funding models to realize the full potential of DOA. Ultimately, this research contributes valuable insights into how DOA can support a more inclusive, accessible, and sustainable academic publishing landscape in the Global South. © 2025 The Author(s). Published with license by Taylor & Francis Group, LLC.