This study aims to analyze the effect of Tax Risk on tax avoidance moderated by company size in basic materials companies listed on the IDX in 2017-2021. The number of samples used in this study were 29 companies with purposive sampling technique. The type of data used is secondary data. This study uses a quantitative approach with data analysis methods and hypothesis testing using panel data regression analysis. The proxy used for tax avoidance is Total book-tax differences (BTD) while the proxy for tax risk is CETR volatility. The results showed that tax risk had a negative effect on tax avoidance. Meanwhile, firm size is able to moderate the effect of tax risk on tax avoidance. Keywords: Tax Risk, Tax Avoidance, Firm Size.