Uranverein

German nuclear weapon project
The German experimental nuclear pile at Haigerloch
Active	1939–1945 (the program effort ceased due to the Fall of Berlin)
Country	Nazi Germany
Allegiance	Germany
Branch	Army Ordnance Office Reich Research Council
Type	Nuclear Weapon Research
Role	development of atomic and radiological weapon
Part of	Wehrmacht
Headquarters	Berlin
Nickname(s)	Uranverein Uranprojekt
Patron	Adolf Hitler
Motto(s)	Deutsche Physik (German Physics)
Engagements	World War II Fall of Berlin Operation Paperclip Operation Alsos Operation Epsilon Russian Alsos
Disbanded	1945 (surrender of Germany)
Commanders
Program Plenipotentiary	Marshal Hermann Göring
Minister for Armaments and Ammunition	Albert Speer
Uranverein' Reichofficer	Walther Gerlach
Reichsdirector of the Reichsforschungsrat	Kurt Diebner

The German nuclear weapon project (German: Uranprojekt; informally known as the Uranverein; English: Uranium Society or Uranium Club) was a scientific effort led by Germany to develop and produce nuclear weapons during World War II. The first effort started in April 1939, just months after the discovery of nuclear fission in December 1938, but ended only months later due to the German invasion of Poland, after many notable physicists were drafted into the Wehrmacht.

A second effort began under the administrative purview of the Wehrmacht's Heereswaffenamt on 1 September 1939, the day of the Invasion of Poland. The program eventually expanded into three main efforts: the Uranmaschine (nuclear reactor), uranium and heavy water production, and uranium isotope separation. Eventually it was assessed that nuclear fission would not contribute significantly to ending the war, and in January 1942, the Heereswaffenamt turned the program over to the Reich Research Council (Reichsforschungsrat) while continuing to fund the program. The program was split up among nine major institutes where the directors dominated the research and set their own objectives. Subsequently, the number of scientists working on applied nuclear fission began to diminish, with many applying their talents to more pressing war-time demands.

The most influential people in the Uranverein were Kurt Diebner, Abraham Esau, Walther Gerlach, and Erich Schumann; Schumann was one of the most powerful and influential physicists in Germany. Diebner, throughout the life of the nuclear weapon project, had more control over nuclear fission research than did Walther Bothe, Klaus Clusius, Otto Hahn, Paul Harteck, or Werner Heisenberg. Abraham Esau was appointed as Hermann Göring's plenipotentiary for nuclear physics research in December 1942; Walther Gerlach succeeded him in December 1943.