This study investigates the effect of audit committee characteristics on financial reporting quality of listed non-financial firms in Nigeria, with firm age examined as a moderating variable. The study covered 92 firms over the period 2012 to 2024. Financial reporting quality was measured using discretionary accruals, while audit committee characteristics were captured through financial expertise, size, independence, and gender diversity. The data were analysed using Ordinary Least Squares regression, with robustness tests conducted to validate the findings. The results reveal that audit committee financial expertise has a positive and significant effect on financial reporting quality, indicating that the presence of members with professional accounting and finance knowledge improves the credibility of reports. Firm age was also found to exert a positive and significant effect, showing that older firms, with stronger governance structures and institutional learning, produce higher quality financial reports. Importantly, the moderating analysis demonstrated that firm age strengthens the effect of audit committee independence on financial reporting quality, suggesting that independence in older firms becomes more effective due to accumulated governance experience and heightened stakeholder scrutiny. Based on the findings, the researchers recommend that firms should prioritise the inclusion of members with financial expertise on audit committees to ensure informed oversight, strengthen independence of audit committees while providing adequate regulatory enforcement to limit managerial influence, and design targeted governance capacity-building initiatives for younger firms to compensate for their lack of institutional maturity compared to older firms.