Objective: Financial statements are the most important set of financial information for economic decision-makings, the validation of which is the main task of the auditor. Auditing is inherently performed with judgment and decision-making, and the results are influenced by the characteristics of the decision-makers, i.e., the audit partners. The audit firm partner, as the leader of a team, assumes the primary responsibility of the audit firm. These partners, like everyone else, have different personalities, including varying degrees of narcissism that may be involved in their audit work.

Method: In order to achieve the research goal, 130 companies among the companies listed on the Tehran Stock Exchange during the years 2016 to 2022 by systematic elimination sampling method, and a total of 910 years-companies were considered for analysis. in this study, audit quality is measured by the two criteria of earnings quality of Dechow and Dichev (2002) and audit error and the size and characteristics of the partner's signature (counterclockwise signature, signature complexity, vertical lines, name writing) have been used to measure partner narcissism

Results: The results show that the auditor's narcissism has a positive relationship with audit quality. Also, in sensitivity tests, it was shown that the narcissism of partner in the first-ranked audit firms has a major and significant effect on improving the quality of the audit.

Conclusion: The results show that narcissistic audit partners due to their commitment to competency and independence, their presence in audit firms leads to improved earning quality and also reduced audit error. In fact, the narcissistic partners are less influenced by customers in order to maintain their popularity and to prove their superiority and as a result, the quality of auditing increases.