The Brazilian Navy (Portuguese: Marinha do Brasil) is the naval service branch of the Brazilian Armed Forces. It is responsible for conducting naval operations, providing maritime security, and enforcing laws and regulations both at sea and within the country's extensive riverine and littoral zones. The Brazilian Navy is one of the world's few blue-water naval forces, capable of regional power projection beyond the country's territorial water and deep into the Atlantic Ocean.

The navy was involved in the Brazilian war of independence and subsequently received most of Portugal's naval forces and bases in South America. The government maintained a sizeable naval force in the initial decades following independence. The navy was later involved in the Cisplatine War, the River Plate conflicts, the Paraguayan War as well as other sporadic rebellions that marked Brazilian history.

By the 1880s, the Brazilian Imperial Navy was the most powerful in South America. After the 1893–1894 naval rebellion, there was a hiatus in developing the navy until 1905, when Brazil acquired two of the most powerful and advanced dreadnoughts of the day which sparked a dreadnought race with neighboring Argentina and Chile. The Brazilian Navy participated in both World War I and World War II, engaging in anti-submarine patrols in the Atlantic.

The modern Brazilian Navy includes British-built guided missile frigates (FFG), locally built corvettes (FFL), coastal diesel-electric submarines (SSK), and many other river and coastal patrol craft. The navy is embarking on modernization efforts to both broaden and enhance its technical and strategic capabilities, such as acquiring amphibious transport docks, procuring logistical support ships, and domestically producing both conventional and nuclear submarines.

In addition to the roles of a traditional navy, the Brazilian Navy also carries out the role of organizing the merchant navy and other operational safety missions traditionally conducted by a coast guard. Other roles include:

The origins of the Brazilian Navy date back to the Portuguese naval forces based in Brazil. The transfer of the Portuguese monarchy to Brazil in 1808 during the Napoleonic wars also resulted in the transfer of a large part of the structure, personnel and ships of the Po

rtuguese Navy. These became the core of the Navy of Brazil.

The Brazilian Navy came into being with the independence of the country. Some of its members were native-born Brazilians, who under Portuguese rule had been forbidden to serve, while other members were Portuguese born who adhered to the cause of independence and foreign mercenaries. A number of establishments previously created by King João VI of Portugal were incorporated into the navy such as the Department of Navy, Headquarters of the Navy, the Intendancy and Accounting Department, the Arsenal (Shipyard) of the Navy, the Academy of Navy Guards, the Naval Hospital, the Auditorship, the Supreme Military Council, the powder plant, and others. The Brazilian-born Captain Luís da Cunha Moreira was chosen as the first minister of the Navy on 28 October 1822.