The following essay explores the significance of Gotthold Ephraim Lessing’s aesthetic theory for Richard Wagner. In his writings and letters, Wagner repeatedly referred to Lessing as a role model for his self-image as an artist, whereby he analogized Lessing’s examination of Voltaire with his own struggle against Meyerbeer. Much more important, however, although largely overlooked by Wagner- and Lessing-scholarship, is Lessing’s role as semiotic mastermind for Wagner’s theory of music and language. This article traces the metamorphosis of key ideas from Lessing’s ‘Laokoon’ and from his ‘Hamburgische Dramaturgie’ in Wagner’s most extensive and explicit theoretical treatise ‘Oper und Drama’.