The Fairy Feller's Master-Stroke is a painting by English artist Richard Dadd. It was begun in 1855 and worked on until 1864. Dadd painted it while incarcerated in the State Criminal Lunatic Asylum of Bethlem Royal Hospital, where he was confined after he murdered his father in 1843. It was commissioned by George Henry Haydon, who was head steward of the hospital at the time.

Richard Dadd was an English painter of the Victorian era, noted for his depictions of fairies and other supernatural subjects, Orientalist scenes, and enigmatic genre scenes, rendered with obsessively minuscule detail. Most of the works for which he is best known were created while he was a patient in Bethlem and Broadmoor hospitals.