The present study explained the effective components' role in the relationship between investment efficiency and tax avoidance. The study's statistical population is the firms listed on the Tehran Stock Exchange. Using the systematic elimination sampling method, 128 companies were selected as the research sample in the 8 years between 2014 and 2021. Data for measuring the variables were collected from the Codal website and the companies' financial statements; preliminary calculations were made in Excel; then, the research hypotheses were analysed and tested using a multivariate regression model with panel data in Stata and Eviwes software. The results show that tax avoidance has a negative effect on investment efficiency. Also, the comparability and readability of financial statements have an inverse effect on the relationship between tax avoidance and investment efficiency. It can be concluded that the comparability and readability of financial statements weaken the inverse relationship between tax avoidance and investment efficiency. Other findings showed that the company's information environment has a direct and significant effect on the relationship between tax avoidance and investment efficiency, and competitive power does not significantly affect the relationship between tax avoidance and investment efficiency.
