Taxes are important financial instrument through which financial tools are gathered (revenues) to cover state expenditures. Taxes are closely related with the development of state administration, fact that has influenced in the expansion of the obligation of paying taxes. Taxes are a specific type of state revenue which are collect by state bodies and other legal and political bodies, from physical and legal persons in return for services which these bodies offer. Tax and taxation is called every payment required by law, in favor of state budget, based on income or property they have, consumption of goods and services they benefit. They are the main source of revenues in state budget. Proportionality and progressivity are two ways of calculating the value of taxes and taxation. The tax system in Albania has been an unexpected development with strong deviations. However, the tax authority made it possible for our country to become stronger by strengthening the country’s finances. In this work are presented mainly thoughts and studies by economists of flat and progressive tax, are also presented evidence concerning the application of a model of taxation in different countries, different debates and polls that individuals and various researches have related with one or another tax.