This study examines the transformation of accounting systems within the context of sustainability reporting and independent assurance services. Transparent and reliable disclosure of sustainability performance is critical in enhancing investor confidence and strengthening corporate reputation. In this respect, the Türkiye Sustainability Reporting Standards (TSRS), enacted in 2025, established a regulatory framework for sustainability reporting in Türkiye. Parallel to this, the Sustainability Audit Regulation, published by the Public Oversight, Accounting and Auditing Standards Authority (KGK), has defined the operational principles for independent audit firms and auditors conducting sustainability assurance engagements.

The study evaluates the role of accounting systems in sustainability reporting by considering the integration of Enterprise Resource Planning (ERP) solutions and digital technologies. Furthermore, the assurance processes are analyzed within the framework of the International Financial Reporting Standards (IFRS S1 and S2), the European Union’s Corporate Sustainability Reporting Directive (CSRD), and the Global Reporting Initiative (GRI) standards. The effectiveness of Türkiye’s regulatory alignment and corporate oversight mechanisms is comparatively assessed, emphasizing the importance of digitalization and quality assurance reviews in sustainability audits.

In conclusion, sustainability reporting and assurance have become strategic components of contemporary accounting practices. The study offers policy recommendations for enhancing sustainability-oriented accounting and audit processes in Türkiye and highlights the significance of aligning with international standards to foster transparency, accountability, and stakeholder trust.