Experiences of different countries with efficient tax systems have shown that the high share of tax resources than non-tax sources could prevent many unpleasant economical events. In other words, an efficient tax system could ensure economic system against many different risks. Tax is also a primary source for developing economy used by government. In this study, we investigate the relationship between economic growth and tax among D8 countries using panel data from 1990 to 2009. The results indicate growth domestic product is the most important factor and these governments could collect more tax as the economic figures improve. The results of our survey show that an increase of one percent on GDP will increase taxable income for about 0.0014119 percent. The tourism has more impact since an increase of one unit in tourism & apos; s income; taxable income will increase for about 10.26257 units. One the contrary to other variables, unemployment has a negative impact on taxable income.