Theatre metaphor has been one of the most used and influential metaphors in the fields of knowledge. Also, this metaphor has played an important role in the field of theatre in explaining the practices that have found an ambivalent life in the liminal space between the everyday and the theatrical, and has been a mediator between the official theatre and the quasi-theatrical experimentations of the 20th century. This metaphor, especially, has had a significant presence and has found complex conceptual implications in the experimentations and manifestos of the Situationist International and the main member of this movement, Gay Debord. Accordingly, in this article, the appearance of this metaphor and its functions in the experimentations and theories of the Situationist International have been described and analyzed. The main stance of this movement was formulated along the Marxist philosophical tradition against the capitalist system and the criticism of this system based on the decoding of its routines and effects in the framework of the concept of “spectacle”. This movement presented manifestos against the capitalist spectacle methods and offered experimental practices as an alternative to these methods. The theatre metaphor has formed an enigmatic situation in these experimentations and manifestos. Although the Situationists have condemned the theatre because of its closeness to the spectacle in the service of capitalist interests, they believe theatre as not a marginal art but a field in which they architecture their practice and theory. Theatre, for Situationists, was conditionally the source of freedom and realization, and in its current form, was the source of lies and illusions. Therefore, the theatre metaphor appears in the thoughts and practices of Situationists, especially Guy Debord, with a double face, which implies both the destructive social function of the theatre and as an art that has internal capacities to resist the capitalist system. On another level, this metaphor refers to the situational technique of detour, which uses the theatre itself against the theatre and wants to detour the theatre to construct a “situation” in the everyday life (a kind of theater without theater).