The Bismarck Archipelago is a group of islands off the coast of New Guinea in the southwestern Pacific Ocean, named in honour of the German chancellor Otto von Bismarck and belonging to Papua New Guinea.

The archipelago includes mostly volcanic islands, the most important of which are:

• Admiralty Islands
• Duke of York Islands
• Mussau Islands
• New Britain
• New Hanover
• New Ireland
• Vitu Islands

The first inhabitants of the Archipelago were the Lapita people.

The first European to find the islands was Dutch explorer Willem Schouten in 1616, but they remained unsettled by Europeans until they became part of the German protectorate of German New Guinea in 1884.

The Australians seized the islands in World War I and kept a League of Nations mandate until Papua New Guinea's independence, only interrupted by Japanese occupation during World War II.