Des Knaben Wunderhorn (The Youth's Magic Horn, referring to a magical device like the cornucopia) is a collection of German folk poems edited by Achim von Arnim and Clemens Brentano, and published in Heidelberg, Germany, between 1805 and 1808.
Selected poems from this collection have been set to music by a number of composers, including Anton Webern, Felix Mendelssohn-Bartholdy, Robert Schumann, Johannes Brahms, Gustav Mahler and Alexander von Zemlinsky.