The OISTAT Theatre Architecture Competition (TAC) is an international ideas competition, aimed at students and emerging practitioners, which is organised every four years by the Architecture Commission of OISTAT (International Organisation of Scenographers, Technicians and Theatre Architects).

Most spaces for the performing arts (drama, music theatre, dance, concerts and other forms) are housed in specialized buildings, built for the purpose.

While there will always be a need for these buildings, there is increasing interest amongst theatre practitioners in the use of existing buildings and settings, which are not purpose built theatres, to present productions. These settings, sometimes known as 'found space', can often provide a unique atmosphere, which resonates with a particular production or style of presentation, in a way that may not be possible in a conventional theatre. While these spaces may lack the technical infrastructure and facilities of a theatre, they can make up for this through the atmosphere provided by the special character of the place, its interaction with the performance and the opportunity to explore less conventional forms of presentation. Many new theatres are also created by converting existing buildings, where the character of the original building contributes significantly to the special atmosphere, and provides a sense of continuity with the past.

These are the basic themes to be explored in this competition.