A crucial component of corporate accountability and transparency is timely financial reporting, especially in developing nations like Nigeria where institutional frameworks may be inadequate. This study examined the effect of audit committee characteristics on financial reporting lag of quoted financial services firms in Nigeria. The specific objectives of the study are to evaluate the effect of audit committee diligence audit committee size, and audit committee financial expertise on financial reporting lag of quoted financial services firms in Nigeria. The research design adopted by the study is ex-post facto research design and the population constitutes all the forty-five (45) financial services firms quoted on the Nigerian exchange group (NGX group) as at 31st December, 2024. Secondary data were extracted from the audited annual reports of the sampled firms from 2015-2024. The study used random effect regression as the techniques of analysis using STATA 17.0 software. The findings revealed that audit committee diligence has an insignificant positive effect on audit report lag of quoted financial services firms in Nigeria. However, audit committee size and audit committee financial expertise has a significant positive effect on audit report lag of quoted financial services firms in Nigeria. The study recommended that firms should maintain an optimal committee size that promotes efficiency without compromising diversity of expertise. The study further recommended that firms should prioritize the appointment of members with strong accounting, auditing, and financial management knowledge. Financially literate committee members are better equipped to understand complex financial issues and ensure quicker completion of audit processes.