Purpose This study aims to investigate the prevalence of reporting on biodiversity actions within the annual reports, corporate social responsibility reports and sustainability reports of UK higher education institutes (HEIs). In addition, the research seeks to examine potential associations between biodiversity and its determinant factors including governance mechanisms-frequency of board meeting, board diversity and Vice Chancellor tenure (VCT) assurance provided by big 4 and environmental awards received by HEIs to support progress towards achieving specific sustainable development goals (SDGs). Design/methodology/approach The authors devised a biodiversity index to measure the extent of reporting on biodiversity actions across four years (2019–2022) encompassing 130 UK HEIs, totalling 520 university-year observations. Using a triangulation approach grounded in three distinct theoretical frameworks – deep ecology, stakeholder and signalling, this study posits that governance mechanisms, assurance practices and environmental awards within UK HEIs influence the extent of reporting on biodiversity actions. Findings This research reveals a notably low level of biodiversity disclosure among UK HEIs. Variability exists across HEIs, with those established before 1992 exhibiting significantly higher biodiversity reporting score compared to their newer counterparts. The study also establishes that governing board mechanisms, specifically VCT and environmental awards received by HEIs exert a significant impact on biodiversity. Conversely, the authors found frequency of board meetings, board diversity positively (insignificant) linked to biodiversity reporting. Assurance and audited by big4 found to have negative (insignificant) relationship with biodiversity. Research limitations/implications This study is limited to UK HEIs, highlighting the need for future research to explore a broader, international sample to enable cross-country comparisons and enhance the generalisability of the findings. More determinants variables can be measured in future research. Originality/value To the best of the authors’ knowledge, this is the first empirical study to investigate reporting on biodiversity actions in 130 UK HEIs over four years. It also links biodiversity reporting to its determinant factors including governance mechanisms (frequency of board meeting, board diversity and VCT), assurance provided by big 4 and environmental awards received by HEIs to support progress towards achieving specific SDGs. The study develops a unique (26-item) biodiversity index encompassing reporting on biodiversity actions. This approach presents novel insights into the governance and accountability practices concerning biodiversity disclosures in the higher education sector. Its originality lies in its focus on biodiversity, which significantly contributes to academic discourse and practical application in sustainability governance within HEIs.