Chrystelle Richard, Claire Grayston, Tom Seidenstein
ABSTRACT The global transition from voluntary to mandatory sustainability reporting has heightened the demand for credible, comparable and decision‐useful sustainability information. In this context, assurance plays a crucial role in reinforcing trust and accountability. Responding to widespread regulatory and market expectations, the International Auditing and Assurance Standards Board (IAASB) developed International Standard on Sustainability Assurance (ISSA) 5000, General Requirements for Sustainability Assurance Engagements , the first comprehensive, profession‐agnostic international standard dedicated to sustainability assurance. In this Perspectives article invited by the Editor‐in Chief, we analyse the rationale, development process and implications of ISSA 5000 within the broader evolution of sustainability reporting and assurance. It examines how the IAASB, in coordination with the International Standards Board of Accountants (IESBA), expedited the standard‐setting process to deliver a globally applicable framework aligned with the public interest. Drawing on extensive stakeholder consultation, the article explores how ISSA 5000 addresses fundamental challenges (materiality, ethical requirements, assurance levels and the use of experts) while balancing conceptual robustness with practical applicability. The study further investigates the emerging challenges of adoption and implementation across jurisdictions, particularly in relation to the European Union's (EU) Corporate Sustainability Reporting Directive (CSRD) and parallel developments in other regulatory regimes. By formalizing a unified assurance framework, ISSA 5000 marks a pivotal step in institutionalizing sustainability assurance as a distinct professional field. The article concludes by outlining future research opportunities on assurance quality, cross‐jurisdictional convergence, practitioner adaptation and the evolving role of technology in shaping assurance practice.