Mapping 24 Years of Sustainability Reporting Assurance Research: A Bibliometric‐Systematic Literature Review

This study provides a comprehensive review of 24 years of research on sustainability reporting assurance. Employing a Bibliometric-Systematic Literature Review (B-SLR) approach, 287 journal articles were analysed to uncover publication trends, citation impact, key journals, theoretical frameworks, methodologies and geographical focus. Science mapping using bibliographic coupling revealed five distinct research clusters: (1) assurance report and practice, (2) determinants of sustainability assurance adoption, (3) effects of assurance on non-financial outcomes, (4) impacts of assurance on capital markets and financial performance and (5) assurance of integrated reports. The findings highlight a marked increase in academic attention, a shift towards quantitative methods and the widespread application of stakeholder, legitimacy, agency and signalling theories. The review further identifies areas of overlap and distinction among clusters, particularly the separation of determinants and impacts of assurance, clarifying conceptual boundaries and enabling targeted future research. By integrating bibliometric indicators with qualitative thematic analysis, the study visually maps the structure and interconnections of the literature, while identifying underexplored topics, including assurance quality, practitioner behaviour, regulatory transitions and technological transformations. Overall, this review offers a consolidated synthesis of existing knowledge and provides a roadmap to advance both theoretical and practical understanding in the evolving field of sustainability assurance.