Jasper Maskelyne (29 September 1902 – 15 March 1973) was a British stage magician in the 1930s and 1940s. He was one of an established family of stage magicians, the son of Nevil Maskelyne and a grandson of John Nevil Maskelyne. He is most remembered for his accounts of his work for the British military during the Second World War, in which he claimed to have created large-scale ruses, deception, and camouflage in an effort to defeat the Nazis.

Maskelyne was born in Wandsworth, London, England in 1902, to magician Nevil Maskelyne and his wife Ada Mary Ardley.

Maskelyne was a successful stage magician. His 1936 Maskelyne's Book of Magic describes a range of stage tricks, including sleight of hand, card and rope tricks, and illusions of "mind-reading".

In 1937, Maskelyne appeared in a Pathé film, The Famous Illusionist, in which he performed his well-known trick of appearing to swallow razor blades.

When the Second World War broke out, Maskelyne, believing his skills could be used for camouflage, joined the Royal Engineers. According to one account, he convinced skeptical officers, including inspector of training Viscount Gort, of his bona fides by camouflaging a machine gun position in plain sight and creating the illusion of the German warship Graf Spee on the Thames using mirrors and a model.

In 1940, Maskelyne was trained at the Camouflage Development and Training Centre at Farnham Castle. He found the training boring, asserting in his book that "a lifetime of hiding things on the stage" had taught him more about camouflage "than rabbits and tigers will ever know". The camoufleur Julian Trevelyan commented that he "entertained us with his tricks in the evenings" at Farnham, but that Maskelyne was "rather unsuccessful" at actually camouflaging "concrete pill-boxes".

Brigadier Dudley Clarke, the head of the 'A' Force deception department, recruited Maskelyne to work for MI9 in Cairo. He created small devices intended to assist soldiers to escape if captured and lectured on escape techniques. These included tools hidden in cricket bats, saw blades inside combs, and small maps on objects such as playing cards.

Maskelyne was then briefly a member of Geoffrey Barkas's camouflage unit at Helwan, near Cairo, set up in November 1941. He was made head of the subsidiary "Camouflage Experimental Section" at Abbassia. By February 1942, it became clear that this command was not successful, so he was "transferred to welfare"—in other words, to entertaining soldiers with magic tricks. Peter Forbes writes that the "flamboyant" magician's contribution was