Legitimacy and SDG Disclosure in Higher Education: A Longitudinal Analysis of Italian Universities' Sustainability Reporting

ABSTRACT Universities are increasingly expected to demonstrate their contribution to the SDGs through sustainability reporting. Drawing on legitimacy theory, this study examines how Italian universities use sustainability reporting to communicate their engagement with the SDGs and whether greater reference to the GRI framework is associated with broader SDG disclosure over time. The analysis covers 124 sustainability reports published by 37 universities between 2017 and 2024. To assess disclosure dynamics, the study develops a Sustainability reporting index (SRI) based on GRI indicators. This is complemented by a longitudinal content analysis aimed at identifying symbolic or substantive legitimation strategies. The findings show that, despite widespread reference to GRI standards, SDG disclosure remains limited and has improved only marginally over time. However, reporting cannot be interpreted as purely symbolic. Instead, universities display hybrid forms of legitimation in which evidence‐based disclosures coexist with rhetorical and value framing. The study contributes to the literature on sustainability reporting in higher education by offering longitudinal evidence on disclosure dynamics, introducing the SRI as a tool for measuring change in reporting, and refining legitimacy‐based interpretations of university SDG reporting.