Mark A. Thomsen (born March 6, 1956) is an American operatic tenor. He is also a professor and artist in residence at Florida Southern College. His performance repertoire includes the history of opera, from Cavalli, Bach, and Mozart, to Puccini, Verdi, and Richard Strauss, and the premieres of operas by composers such as Dominick Argento, Leonard Bernstein, Carlisle Floyd and Lowell Liebermann.