This study aims to determine whether auditor’s reputation and auditor’s opinion have an effect on stock prices in the following year in companies listed on the IDX Main Board Index from 2016 to 2020. Regression analysis is used in this study by adding control variables and year fixed effect. The data used in this study are obtained from the companies listed in the IDX Main Board Index. Panel data are taken from the companies’ annual reports for the period of 2016-2020. The total number of samples is 200 companies. The results show that, partially, auditor’s reputation has an effect on stock prices in the following year, while auditor’s opinion has no effect on stock prices in the following year. However, simultaneously, both variables have an effect on stock prices in the following year. This means that the election of the BIG4 Accounting Firms as the company’s auditor has proven to increase the value of companies listed on the IDX Main Board Index in the following year.