Robert the Devil, or The Nun, the Dun, and the Son of a Gun is an operatic parody by W. S. Gilbert of Giacomo Meyerbeer's grand opera Robert le diable, which was named after, but bears little resemblance to, the medieval French legend of the same name. Gilbert set new lyrics to tunes by Meyerbeer, Bellini, Offenbach and others.

Sir William Schwenck Gilbert was an English dramatist, librettist, poet and illustrator best known for his collaboration with composer Arthur Sullivan, which produced fourteen comic operas. The most famous of these include H.M.S. Pinafore, The Pirates of Penzance and one of the most frequently performed works in the history of musical theatre, The Mikado. The popularity of these works was supported for over a century by year-round performances of them, in Britain and abroad, by the repertory company that Gilbert, Sullivan and their producer Richard D'Oyly Carte founded, the D'Oyly Carte Opera Company. These Savoy operas are still frequently performed in the English-speaking world and beyond.