Porezni sustav, kao i porezne stope koje definira pojedina država, razlikuju se od države do države na temelju gospodarskog stanja i mogućnosti u nacionalnoj ekonomiji. Nema države bez poreza ni poreza bez države, pa se može zaključiti da je porez po vremenu i cilju vezan za ustrojstvo države. Cilj ovog rada je detaljno opisati što je zapravo porezni sustav, porezna sposobnost i osnovica, kakve porezne stope postoje, koja su temeljna načela oporezivanja te kako porezi funkcioniraju u Republici Hrvatskoj. Može se vidjeti da je porez vrlo bitna sastavnica neke zemlje jer se upravo porezima i samim poreznim sustavom puni državni proračun neke države koji se dalje koristi za potrebe obrazovanja, zdravstva,infrastrukture, javnog reda i mira, zaštite i prava građana.

Tax systems, as well as tax rates which the defines individual states, differ from country to country based on the economic situation and opportunities in the national economy. There is no country without taxes and there are no taxes without a country, so it can be concluded that taxes are related to the organization of the state by time and goal. The aim of this paper is to describe, in detail, what a tax system actually is, the tax ability and base, what kind of tax rates exist, and what the basic principles of taxation are and how taxes work in the Republic of Croatia. It can be noted that the tax system is a very important component of a country, since the national budget of a country is determined via taxes and the tax system, and that tax revenue is used for education, health, infrastructure, public law and order, and protection and the rights of citizens.