Friedrich "Fritz" Saxl (8 January 1890, Vienna, Austria – 22 March 1948, Dulwich, London) was the art historian who was the guiding light of the Warburg Institute, especially during the long mental breakdown of its founder, Aby Warburg, whom he succeeded as director.
Saxl studied in his native Vienna under Franz Wickhoff, Julius von Schlosser and Max Dvořák, who oversaw his dissertation on Rembrandt.
He served in the Austro-Hungarian army as a lieutenant on the Italian front for the duration of World War I.
With the Nazi regime in power, Saxl was instrumental in moving the Warburg Institute to safety in London in 1933, coming with it himself and settling in England, becoming a British citizen in 1940.
His efforts at maintaining the Warburg Institute came at the cost of his own scholarly output, which was mostly restricted to papers and lectures.