Earnings management remains a persistent challenge in financial reporting, particularly among listed financial service firms in Nigeria, where managerial discretion in accounting choices can undermine the credibility of financial statements and investor confidence. Despite the existence of audit committees as key corporate governance mechanisms, concerns persist regarding their effectiveness in constraining opportunistic financial reporting practices. This study examines the effect of audit committee attributes on earnings management of quoted money deposit banks and insurance companies in Nigeria from 2015 to 2024. The study adopts an ex-post facto research design and covers a population of 29 quoted money deposit banks and insurance companies, from which a sample of 20 firms was selected. Secondary data were analyzed using multiple regression techniques with the aid of STATA 13, while the Generalized Least Squares (GLS) method was employed to address issues of non-normality and heteroscedasticity. The findings reveal that audit committee gender diversity has a significant negative effect on earnings management, while audit committee meetings have an insignificant effect. Conversely, audit committee expertise shows a significant but positive relationship with earnings management. The study concludes that audit committee gender diversity serves as an effective constraining mechanism against earnings management, whereas audit committee meetings do not significantly influence earnings behavior, and audit committee expertise unexpectedly enhances earnings management. It recommends that boards of listed financial service firms prioritize the appointment of female directors with relevant financial or accounting expertise rather than mere token gender representation to strengthen audit committee effectiveness and improve financial reporting quality.