The Landsmannschaft Ostpreußen ("Homeland Association of East Prussia") is a non-profit organization for Germans who were evacuated or expelled from East Prussia during World War II and as well as people who emigrated in more recent times, exercising their right to German citizenship, based on a 1913 German law. It was formed on 3 October 1948 by East Prussian refugees in West Germany.

The organization's current president is Stephan Grigat. Its seat is in Hamburg, and it is a member of the Bund der Vertriebenen. Its official newspaper is the Preußische Allgemeine Zeitung. The Bund Junges Ostpreußen is a subsidiary youth organization of the Landsmannschaft Ostpreußen; its predecessor, Junge Landsmannschaft Ostdeutschland, was disassociated from the parent organization in 2000.

• 1948–1951: Ottomar Schreiber
• 1952–1966: Alfred Gille
• 1966–1971: Reinhold Rehs
• 1971–1974: Joachim Freiherr von Braun
• 1974–1979: Hans-Georg Bock
• 1979–1990: Ottfried Hennig
• 1990–1992: Harry Poley
• 1992–2010: Wilhelm von Gottberg
• 6 November 2010 – present: Stephan Grigat

• Landsmannschaft Ostpreußen (in German)
• Bund Junges Ostpreußen (in German)
• Preußische Allgemeine Zeitung (in German)