Sustainability assurance – a review and research agenda

Purpose This paper systematically reviews the existing litearture on sustainability assurance, integrating insights from firms’ motivations, theoretical frameworks, assurance standards, and influencing factors of sustainability assurance quality. Design/methodology/approach This paper reviews and synthesises the literature on sustainability assurance within the accounting and finance domain. It systematically examines prior research to distill the core themes, theoretical foundations, methodological approaches, and key findings of sustainability assurance works. Findings Building on a systematic review of the sustainability assurance literature, this paper advances understanding of the field from multiple dimensions. Specifically, by synthesising and extending prior evidence on value creation, risk mitigation, legitimacy building, and the strengthening of internal control systems, it deepens insights into firms’ motivations for seeking sustainability assurance. Moreover, drawing on the perspectives of corporate social relations and the organisational environment, the study systematically integrates the main theoretical foundations of sustainability assurance and demonstrates how firms’ responses to institutional and stakeholder expectations shape the adoption, design, and implementation of assurance practices. At the same time, it critically identifies the limitations of current sustainability assurance standards—particularly regarding comparability, scope, and implementability—and reveals how these constraints affect assurance effectiveness and practical application. Finally, by incorporating the perspectives of assurance practitioners and sustainability report providers, the paper systematically identifies the key determinants of sustainability assurance quality. Meanwhile, this study highlights limitations in assurance quality measures and emphasises the need for more precise and multidimensional assessment approaches. Originality/value This paper highlights critical issues in sustainability assurance and proposes targeted improvements. Limited stakeholder engagement undermines assurance effectiveness, highlighting the need to better align managerial objectives with external stakeholder expectations. Moreover, ensuring credible sustainability assurance requires a clearer separation between financial audit and sustainability assurance functions, the strengthening of internal information systems, and the allocation of adequate organisational resources.