Tax is one of the most important sources of government income whose acceptance by the people and mode of implementation by the government depend on the cultural characteristics of each country. However, it is possible that some consider the tax as a one-way payment from people to government; therefore, there are resistances in paying the taxes. But if the culture of tax payment is institutionalized in the society, most of the problems will be resolved. The purpose behind this research is investigating the factors responsible for tax evasion in South Khorasan province. The research is practical in terms of purpose and descriptive in terms of data acquisition method, and it is of the survey-based type. The data have been gathered from 117 questionnaires based on an opinion poll of tax experts in South Khorasan; the Likert scale has been used for measurement of variables. It is important to note that SPSS and R software have been exploited to test the research hypotheses, and results show that there is a positive and meaningful relationship between cultural and economic factors and legal-political components on the one hand, and tax evasion on the other.