Oberon, or The Elf-King's Oath (J. 306) is a 3-act romantic opera with spoken dialogue composed in 1825–26 by Carl Maria von Weber. The only English opera ever set by Weber, the libretto by James Robinson Planché was based on the German poem Oberon by Christoph Martin Wieland, which itself was based on the epic romance Huon de Bordeaux, a French medieval tale. It was premiered in London on 12 April 1826.
Against his doctor's advice, Weber undertook the project commissioned by the actor-impresario Charles Kemble for financial reasons. Having been offered the choice of Faust or Oberon as subject matter, he travelled to London to complete the music, learning English to be better able to follow the libretto, before the premiere of the opera.