Mark Nelson (born September 26, 1955) is an American actor mostly known for playing Ned in Friday the 13th (1980). He has appeared in the Broadway productions of Angels in America (2018), Cabaret (2016), After the Fall, The Invention of Love, Three Sisters, Picasso at the Lapin Agile (Obie Award), A Few Good Men, Rumors, Broadway Bound, Biloxi Blues, Brighton Beach Memoirs, and Amadeus. He teaches theater at Princeton University and HB Studio in New York, where he studied acting with Uta Hagen.