Elisabeth von Magnus (née Countess Elisabeth Juliana de la Fontaine und d'Harnoncourt-Unverzagt; born 29 May 1954 in Vienna) is an Austrian classical mezzo-soprano.
Magnus is the daughter of conductor Nikolaus Harnoncourt and violinist Alice Harnoncourt. She has been married twice and has three children. Her second husband is tenor, chorus master and conductor Simon Schouten but she is known professionally by the surname of her first husband Ernst-Jürgen von Magnus.
Elisabeth von Magnus studied recorder in Vienna, theater at the Mozarteum in Salzburg and voice with Hertha Töpper at the Conservatory of Munich.
She appeared at the Salzburg Festival first in 1993 in Mozart's Great Mass in C minor as well as in L'incoronazione di Poppea and Vespro della Beata Vergine 1610 of Monteverdi. She took part in several projects with Nikolaus Harnoncourt, such as a production of Mozart's Le nozze di Figaro staged by Jürgen Flimm in Amsterdam.
Her US debut in 1991 was in Bach’s St Matthew Passion with the Los Angeles Philharmonic conducted by Peter Schreier.
She took part in the project of Ton Koopman and the Amsterdam Baroque Orchestra & Choir to record the complete vocal works of Johann Sebastian Bach.