Twentieth-century theatre describes a period of great change within the theatrical culture of the 20th century, mainly in Europe and North America. There was a widespread challenge to long-established rules surrounding theatrical representation; resulting in the development of many new forms of theatre, including modernism, expressionism, impressionism, political theatre and other forms of Experimental theatre, as well as the continuing development of already established theatrical forms like naturalism and realism.

Naturalism is a movement in European drama and theatre that developed in the late 19th and early 20th centuries. It refers to theatre that attempts to create an illusion of reality through a range of dramatic and theatrical strategies. Interest in naturalism especially flourished with the French playwrights of the time, but the most successful example is Strindberg's play Miss Julie, which was written with the intention to abide by both his own particular version of naturalism, and also the version described by the French novelist and literary theoretician, Emile Zola.