<p>This research article presents a bibliometric analysis of environmental, social and governance (ESG) research over the past two decades. Analysing 2,243 academic publications from the Web of Science and Scopus databases, the study charts the growth of ESG research and traces the evolution of core themes. The results indicate a sharp acceleration in the ESG literature in recent years, with the highest number of publications recorded in 2023. Using keyword co-occurrence and thematic evolution analyses, the study identifies three phases that progress from fragmented and emerging themes to more integrated and structured clusters. Over the entire period, five main research themes emerge: ESG investment, ESG performance, ESG disclosure, ESG ratings, and sustainability reporting. Building on these themes, the discussion highlights several unresolved issues, including uncertainty about the financial effects of ESG investment and performance, limited exploration of investors’ heterogeneity, and concerns about greenwashing and divergence in ESG ratings. It also reveals an incomplete understanding of how governance mechanisms shape ESG disclosure and limited evidence on the role of emerging digital technologies, such as artificial intelligence (AI), in enhancing sustainability reporting while raising ethical, regulatory, and operational challenges.</p>