Improving the efficiency of quality management systems is an important challenge for the business sector and the economy as a whole. Based on the fact that the quality system is the most important tool on which companies are based, to achieve the desires and expectations of customers and consumers, as well as to achieve profitability and continuity in the labor market in the long term. This study contributes to the efforts made by researchers to find effective ways and means that allow companies to measure and improve the effectiveness of their quality management systems, benefiting from the internal audit process of ISO 9001 quality systems, expanding the scope of audit to include audit of quality indicators and key performance indicators for the performance of the quality system as a whole, combined with the verification of compliance of the system with ISO 9001: 2015. The aim of the study is to improve the efficiency of the quality management system through internal audit of QMS.