Given the historical dominance of fantasy in British children’s literature and the American predisposition for realism, it is somewhat surprising that Roald Dahl’s children’s books were initially better known and appreciated in the US than in Britain.  This paper argues that Dahl's work was peculiarly suited to a US audience because his  hyperbolic children’s fantasies appealed to the American love of overstatement, a hallmark of that most American of storytelling forms: the tall tale. Another factor in Dahl's success in the US is his deployment of a brand of humour which might be described as grotesque caricature, a mode aligned with the Gothic genres which have been popular in the United States.