Based on the Agency theory, there is a conflict of interest between management and ownership. The separation of financial and control features leads to the Agency cost that is achieved by managers' opportunistic behaviors with respect to information asymmetry. The audit committee is considered as one of the components of the firm's governance framework and is a determinant factor in the financial reporting process, which increases the credibility of the audited financial statements. Therefore, based on this argument, the present study examines the relationship between the effectiveness of the audit committee and audit quality. To this end, four comprehensive criteria including size, expertise, independence, and number of meetings of the audit committee were used to measure the effectiveness of the audit committee and also, three comprehensive criteria including the auditors' fees, the auditor's expertise, and size of the audit firm were used to measure the audit quality. The research hypothesis was also tested using a sample of 53 companies accepted in Tehran Stock Exchange during 2012 to 2016. Findings of the research indicate a positive and significant relationship between the effectiveness of the audit committee and the audit quality.