The aim of this study was to investigate the effect of oil prices and fluctuations on the return on assets of companies listed in the chemical and refining industry of the Tehran Stock Exchange to collect data related to research in companies listed on the stock exchange. The method of the present study was applied in terms of purpose and regression analysis in terms of method. The statistical population of this study includes companies listed on the Tehran Stock Exchange and systematic screening or elimination method was used to select the sample. In this way, first, all the companies that could participate in the sampling were selected and then, among them, the companies that were not eligible were eliminated, and finally, the companies that remained were selected for the test. The research period was considered between 2012 and 2018. In this study, the data required to test the research hypotheses were extracted from the annual financial statements of companies (Codal site) and the website of the Stock Exchange Organization. In this way, first using quantitative methods including tools in descriptive statistics, such as mean, standard deviation of the data used was analyzed and to test the hypotheses of this study and determine the relationship between independent and dependent variables, econometric models and hypotheses were used. The corresponding panel multivariate regression method was examined. The results of examining the hypotheses showed that oil price fluctuations affect the return on assets of chemical companies that are members of the Tehran Stock Exchange. Oil sanctions affect the relationship between oil price fluctuations and the return on assets of chemical companies that are members of the Tehran Stock Exchange.