Alan Louis Charles Bullock, Baron Bullock (13 December 1914 – 2 February 2004) was a British historian. He is best known for his book Hitler: A Study in Tyranny (1952), the first comprehensive biography of Adolf Hitler, which influenced many other Hitler biographies. Dr. Bullock, later Sir Alan and eventually a life peer, diagnosed the malignancies of dictatorship and tyranny that plagued 20th-century Europe. He twinned two such dictators in one of his later studies, Hitler and Stalin, Parallel Lives (1991, Knopf).

He was the last of three brilliant Oxford historians whose views influenced thought in the English-speaking world and beyond, even when their own views diverged. The others were A. J. P. Taylor and Hugh Trevor-Roper who, for instance, offered a more nuanced interpretation of Hitler than did Dr. Bullock. While Dr. Bullock originally portrayed Hitler as a diabolical charlatan and cynical opportunist without convictions, Trevor-Roper saw him as an ideologue and demagogue convinced of his own perspective.