The audit opinion, as the most important output of the audit process, reflects the independent auditor’s professional judgment regarding the fairness of the financial statements and plays a decisive role in stakeholders’ decision-making. In this regard, corporate sustainability performance, which reflects a firm’s attention to Environmental, Social, and Governance (ESG) dimensions, can be considered as an indicator of financial reporting quality and risk management. On the other hand, Audit Committee Independence (AUDC_IND), as one of the key pillars of corporate governance, facilitates effective oversight of financial reporting and audit processes. This study seeks to examine the potential role of corporate sustainability performance and AUDC_IND in shaping audit opinion. Accordingly, the aim of this research is to determine the effect of corporate sustainability performance on audit opinion, considering the moderating role of AUDC_IND in companies listed on the Tehran Stock Exchange. To achieve this objective, two hypotheses were developed. For hypothesis testing, a systematic elimination (systematic sampling) method was used to select a sample of 150 companies from among firms listed on the TSE over the period 2019 to 2024 (1398–1403 in the Iranian calendar). This study is applied in nature, and the research models were estimated using multiple regression analysis. The results indicate that corporate sustainability performance has a negative and significant effect on modified audit opinions. Furthermore, AUDC_IND strengthens the relationship between corporate sustainability performance and modified audit opinions.