Tax Law is the set of legal rules and principles that define the tax treatment of the citizens of a State, while defining the powers of the State and the process, both in regards to the collection and the imposition of taxes. Moreover, tax law includes the provisions defining the legal framework to address and combat tax evasion.

The tax law can be characterized as an enforcement law, while included in Public Law, as it relates to the managerial decisions of the State, but it can also be approached independently, due to the volume of operations and its association with the Civil Law.