This study introduces the concept of "postmodern avant-garde" drama, a term that the researcher has coined to characterize the diverse aspects of postmodernism expressed in Gertrude Stein''s avant- garde drama. There are three unifying principles that characterize "the postmodern avant-garde" drama: the labyrinthine discourse, language- and theory-oriented play writing, and gender/genre trouble. This dissertation attempts to prove that all the unifying elements of "the postmodern avant- garde" pervade nearly all of Stein''s works. To achieve these objectives, seven plays have been selected among Stein''s plays since they are relevant to the topic of this study. The selected plays for this study are: What Happened. A Five Act Play (1913), Ladies'' Voices. Curtain Raiser (1916), Circular play (1920), Four Saints in Three Acts (1927), They Must. Be Wedded. To Their Wife (1931), A Play Called Not and Now (1936), and Listen to Me (1936). The study is divided into an introduction, three chapters and a conclusion.