The energy sector is a risky sector, in which fixed capital investments are very high. Therefore, enterprises in the energy sector must have a financially sound structure. From this point of view, the aim of this study is to assess the financial performance of the companies in the energy sector with the Entropy based ARAS method. This study is important in terms of examining the soundness of financial structures of enterprises in the energy sector, which is the driving force of countries. As a sample, businesses in Borsa İstanbul Electricity, Gas and Steam Sector were selected. In the study, financial data belonging to 2018 were used. According to the result of the Entropy method, in which the criterion weights are determined, the most important financial ratios are found as equity turnover ratio, debt to equity ratio and total assets turnover ratio, respectively. The fact that financing and financial structure ratios are the most important ratios can be attributed to the high starting and operating costs of the energy sector because these high costs must be supported by a solid financial structure. According to the result of the ARAS method, in which weights obtained from the entropy method are used, ENJSA, AKSEN and ZOREN are found to be the companies with the highest financial performance, respectively.