The Brazilian legal system is based on Civil Law tradition. The Federal Constitution, in force since October 5th, 1988, is the supreme rule of the country and is the characterized by its rigid written form. The Constitution organizes the country as a Federative Republic, formed by the indissoluble union of the states and municipalities and of the Federal District. The 26 federate states have powers to adopt their own Constitutions and laws; their autonomy, however, is limited by the principles established in the Federal Constitution.

Municipalities also enjoy restricted autonomy as their legislation must follow the dictates of the Constitution of the state to which they belong, and consequently to those of the Federal Constitution itself. As for the Federal District, it blends functions of federate states and of municipalities, and its equivalent to a constitution, named Organic Law, must also obey the terms of the Federal Constitution.

The Judiciary is organized into federal and state branches. Municipalities do not have their own justice systems, and must, therefore, resort to state or federal justice systems, depending on the nature of the case. The judicial system consists of several courts. The apex is the Federal Supreme Court and is the guardian of the Constitution. Among other duties, it has exclusive jurisdiction to: (i) declare federal or state laws unconstitutional; (ii) order extradition requests from foreign States; and (iii) rule over cases decided in sole instance courts, where the challenged decision may violate the Constitution.

The Superior Court of Justice is responsible for upholding federal legislation and treaties. The five Regional Federal Courts, have constitutional jurisdiction on cases involving appeals towards the decision ruled by federal judges, and are also responsible for cases of national interest and crimes foreseen in international pacts, among other duties. The jurisdiction of the Federal Judges include: being responsible for hearing most disputes in which one of the parties is the Union (State); ruling on lawsuits between a foreign State or international organization and a municipality or a person residing in Brazil; and judging cases based on treaties or international agreements of the Union against a foreign State or international body.

State-level justice in Brazil consists of state courts and judges. The states of Brazil organize their own judicial systems, with court jurisdiction defined in each state constitution, observing that their legal scope is limited by those that do not concern the federal judicial ordainment.