​The main purpose of this research is to investigate the impact of capital structure and ownership structure on the audit committee effectiveness. To achieve the objectives of the study, a sample of 82 service and industrial firms that have been listed on Amman stock exchange (ASE) during the years 2014 to 2018 with a 388 observation is used. Descriptive statistics and multiple regression analysis are used to analyze the data and test the hypotheses. Audit committee’s index is calculated using many variables including the independence of the committee, the independence of its chairman, knowledge and expertise of its members, size of the audit committee and frequency of meetings. The study results revealed that there is a negative significant impact for the concentrated ownership and managerial ownership on the audit committee effectiveness, whereas the institutional and the foreign ownership don’t show a significant impact. The results also revealed that there is a positive significant impact for the capital structure on the audit committee effectiveness. The study concentrated on non-financial sectors, the financial sector was excluded from this research sample due to the specific regulation and the specific characteristics related to it. The study results direct the attention of the decision-makers to take the appropriate measures that can improve the effectiveness of the audit committees and in turn help in reserving the interests of the various investing groups. The research significance stems from its expected contribution and practical implications in the improvement of audit committee effectiveness. It also holds a theoretical significance as a pioneer study, up to the knowledge of the researchers, which investigates the impact of ownership structure and capital structure on the audit committee effectiveness in the Jordanian context​