Abstarct: Abstract The purpose of this study is investigating the, the leverage effect of sentiment on the stock returns of companies listed on the Tehran Stock Exchange. The statistical sample of the present study includes 98 selected companies during the years 1392 to 1398. Excel and EViews softwares have been used to classify and analyze the data. In this research investors' sentiment and companies' stock returns have been used respectively as independent and dependent variable and the variables of company size, price-to-income ratio and logarithm of trading volume have been used as control variables. To test the research hypotheses, quantile regression tests and slope equality and the method of "principal component analysis" have been used. The results show that investors' abnormal sentements have a positive and significant effect on stock returns. According to behavioral finance theory, the psychological factors of investors play an important role in their decision making and also the tendencies of investors' sentiments can change the stock returns. Therefore, investors' trading behavior has a negative effect on returns and also the results showed that abnormal sentiments and investors' trading behaviors have a leverage effect on companies' returns