Fritz Fischer (5 March 1908 – 1 December 1999) was a German historian best known for his analysis of the causes of World War I. In the early 1960s Fischer advanced the controversial thesis at the time that responsibility for the outbreak of the war rested solely on Imperial Germany. Fischer's anti-revisionist claims shocked the West German government and historical establishment, as it made Germany guilty for both world wars, challenging the national belief in Germany's innocence and converting its recent history into one of conquest and aggression.

Fischer was named in The Encyclopedia of Historians and Historical Writing as the most important German historian of the 20th century. In 1984, he was elected an honorary member of the American Historical Association.