In recent years, the relationship between ethics and tax evasion has become a fascinating issue among economics researchers. Most studies on tax evasion have taken either an economics or public finance perspective and few studies have investigated tax evasion from the perspective of ethics. There are several factors, which play a role for the formation of tax morality. To determine the extent of support for the various arguments that exists in Iran, this study has constructed a survey questionnaire that includes 15 historical arguments and three newer arguments, and these questionnaire are distributed among students of faculty of administrative and economics at the University of Isfahan. The other important purpose of this study is to measure the extent of tax morality and then investigate the effect of demographic variables like age, gender, education, income and ethnicity of respondents to tax morale. The results of both OLS and ordered probit model show that age and income have positive and significant effect on tax morale, but the effect of ethnicity is negative and significant. However, education and gender are only significant in the ordered probit model.