This study aims to explore the provision of web-based sources and services through the websites of university libraries in India. The present study adopted a content analysis method for examining various web-based library services and web-based sources provided through the university library websites with a checklist. A total of 50 top-ranked Indian universities were listed from the National Institutional Ranking Framework (NIRF) ranking list for the year 2020 in the category university. From these universities to be included as a sample for the present study; each university must have an independent library website. Secondly, the university library should be offering web-based library services and resources through the library website. Based on these criteria, 42 library websites were shortlisted as a sample for this study. The study found that majority of the libraries were offering traditional library services such as referral service, and library catalogue in a web-based environment more extensively compared to innovative and modern present-day services like library application (App), Instant Messaging (IM), and virtual library tours. Moreover, libraries are yet to explore the full potential of social media services and web 2.0 tools. A majority of the library websites were lagging in the provision of these services. It is suggested that libraries should make efforts to provide social media services extensively as the current generation are the predominant users of social media; hence it is evident on the libraries' part to make efforts to reach out to a wide population of their library users. This research is the first study of its kind highlighting the significance of university library websites in the provision of web-based services and sources for sustainability, and exploring the role of academic libraries in the promotion of sustainable development by processes like collection development on sustainable development themes, developing information literacy skills, spreading awareness, and organizing events on sustainable development and related areas.