Erik Lönnroth (1 August 1910 in Gothenburg– 10 March 2002) was one of the most notable Swedish historians of the 20th century. He was a life member of the Swedish Academy from 1962 and member of various faculties.
Lönnroth was an influential author. The subjects he did historical research includes the Kalmar Union, Lawrence of Arabia, King Gustav III of Sweden and the rebel leader Engelbrekt Engelbrektsson. Lönnroth took the history subject to a new level in Sweden. He developed and refined the critical theory of historiography that his mentor, Curt Weibull, had introduced. He also did pioneering work on the medieval economical history of Sweden and on psychohistory.