The Hierarchy of Effective Factors on Corporate Tax Avoidance Because of the information asymmetry within taxpayers and governments, commonly, the taxpayers try avoid the payment of tax. The problem can be explained by Agency theory. On the other hand, governmants try to maximize receiving tax by recognizing risky taxpayers and researchers try to recognize effective factors on tax avoidance. The aim of the research is the hierarchy of effective factors on corporate tax avoidance on Tehran stock exchange. In this research, first, 37 quantity factors are recognized that affect on corporate tax avoidance in 8 dimensions by interview with academic and professional experts that can be measure by corporate reports.
   Then the factors and dependent variable are measured and are tested the efficacy of the dimensions by structural equation model (SEM). Finally, based on confirmed dimensions, hierarcy is done by contributed analytic hierarchy process quastionaries with same experts. Statistic population in this research involves 77 companies listed in Tehran Stock Exchange during the period 2013-2017 that are selected by systematic delete. The interview with experts done at 2017 and questionaries contributed at 2018. Results show that the hierarchy of effective factors on corporate tax avoidance is: trading factors, corporate governance factors, auditor factors, financial reporting factors, industrial factors, public attributes, capital market factors and social factors.