Theatre "In The Round" is any theatre space in which the audience is seated on all sides of the stage, either in a circle, or in a variety of surrounding sections. The stage itself in this arrangement is typically round, square, or triangular, with actors entering and exiting through the audience from multiple directions. Such a space is usually configured with the stage on an even level with or lowered below the audience in a "pit" or "arena" formation. The configuration lends itself to high-energy productions, and is especially favored by producers of classical theatre such as Greek or Elizabethan theatre. Theatre in the round was common in ancient theatre, particularly that of Greece and Rome, but was not widely explored again until the latter half of the 20th century.

Theater in the round presents particular problems for directors, due to the fact that actors at all times have their back facing some members of the audience. However, it also allows for particularly intimate and realistic dynamic staging. The configuration is also commonly employed when theatrical performances are presented in non-traditional spaces such as restaurants, public areas such as fairs or festivals, or street theatre

Theatre performed "in the round" is still fairly uncommon, though several smaller companies and some prominent producers (notably New York's Circle In The Square) perform theatre in the round on a regular basis.

An extreme form of theatre in the round is the promenade production, in which there is no separation between the acting space and the audience space, and the audience is permitted and encouraged to come very close to the actors as they perform.