The Victual Brothers (German: Vitalienbrüder) were a loosely organized guild of privateers who later turned to piracy. They affected maritime trade during the 14th century in both the North and Baltic Seas.
During 14th century, Queen Margaret I of Denmark was battling Albert of Mecklenburg for Scandinavian supremacy. Albert had been King of Sweden since 1364 and Duke of Mecklenburg since 1383. The Vitalian Brotherhood were hired in 1392 by the Dukes of Mecklenburg to fight against Denmark, after Queen Margaret had imprisoned Albert and his son Eric of Mecklenburg in order to subdue the Kingdom of Sweden. While Queen Margaret's forces were besieging , the blockade runners who came to be known as the Victual Brotherhood, engaged in war at sea and shipped provisions to keep the city supplied. The name Victual Brothers is derived from the Latin word "victualia" — meaning provisions — and refers to their first mission, which was to supply the besieged city.
The Victual Brothers were organised as a brotherhood or guild. Their main naval enemy in 1392 was the powerful Hanseatic town of Lübeck, which supported Denmark in the war. Apart from Lübeck, the Hanseatic League initially supported the Victual Brothers. Most of the Hanseatic towns had no desire for a victory for Denmark, with its strategic location for control of the seaways. For several years from 1392, the Victual Brothers were a strong power in the Baltic Sea. They had safe harbours in the cities of , Ribnitz, Wismar and Stralsund. They soon turned to open piracy and coastal plunder. In 1393 they sacked the town of Bergen for the first time and in 1394 they conquered Malmö. They occupied parts of Frisia and Schleswig. They also plundered Turku, Vyborg, Styresholm, Korsholm and Faxeholm castle at Söderhamn in Hälsingland.