This paper examines the association between the attributes of the audit committees (ACs) and the audit report timeliness for UK FTSE350 companies over the period 2017 to 2019. In particular, we investigate the impact of AC's attributes, namely, independence, gender, financial expertise, activity and size; as prescribed by the UK Corporate Governance code (2018) on the audit report lag (ARL). To this end, we employ the OLS regression with robust standard errors based on 633 firm-year observations. Our results indicate that AC's independence and meeting frequency are associated with a reduction in audit report delay. However, the results also indicate that AC's gender, financial expertise and size do not influence the audit report timeliness. More interestingly, the UK listed companies, which issue their annual reports during the busy reporting period tend to have longer ARL. In contrast, the high audit fees are significantly associated with shorter ARL. Contrary to the propositions of the critical mass theory, additional analysis reveals that high representation of female directors in ACs would deter the financial reporting timeliness, since it is associated with longer ARL. Our results are also robust for alternate measures for ACs' attributes of size, activity and expertise.The findings of our study highlight the importance of ACs, as an internal governance mechanism, in enhancing the timeliness and the quality of companies' financial reporting. It accentuates the role of independent director, as well as the ACs' meeting, in alleviating any disputes and settling any issue that might hinder the external auditors to release timelier audit report. Our findings also direct the attention of the UK regulators to the importance of providing a clearer definition of the financial expertise required by ACs' members. In addition, our results also direct the attention of the UK companies to the importance of choosing the female directors' members in ACs based on their qualification and expertise, rather than their mere representation to satisfy the UK CG recommendation.