The Saint in London is a 1939 British crime film, the third of eight films in RKO's film series featuring the adventures of Simon Templar, alias "The Saint".

It stars George Sanders as Templar and was produced by William Sistrom. John Paddy Carstairs directed. Lynn Root and Frank Fenton wrote the screenplay based on Leslie Charteris' short story "The Million Pound Day", which was published in the 1932 collection The Holy Terror, published in the US as The Saint vs. Scotland Yard.