Marshall W. Mason is an American theater director, educator and author. He was the founder and for eighteen years, artistic director of the Circle Repertory Company in New York City.
Born in Amarillo, Texas, Mason graduated in 1961 with a B.S. in theater from Northwestern University, where he directed Cat on a Hot Tin Roof at the age of 19, winning his first award for directing. Upon graduating, he relocated to Manhattan, where he began working in the off-off-Broadway theater scene in such venues as Caffe Cino, the La MaMa Experimental Theatre Club, and Judson Poets Theatre. He made his off-Broadway debut in 1964 with a revival of the Henrik Ibsen play Little Eyolf. The following year he directed Balm in Gilead, his first collaboration with playwright Lanford Wilson. Since then he has directed more than sixty productions of Wilson's plays, which Playbill has identified as the longest collaboration between a playwright and director in the history of the American theater. Among these are The Hot l Baltimore, for which he won his first Obie Award for Distinguished Direction, Fifth of July, Talley's Folly, Angels Fall, Burn This, Redwood Curtain, and Book of Days.