Bi-Directional Optimality Theory: An Application of Game Theory Paul Dekker, Robert van Rooy Abstract: Optimality Theory catches on in linguistics, first in phonology, then in syntax, and recently also at the semantics / pragmatics interface. In this paper we point at some parallels between some principles employed in optimality theoretic interpretation, and some notions from the well studied field of Game Theory. Optimality theoretic interpretation can be defined as what we call an "interpretation game", and optimality itself can be viewed as a solution concept for a game. More in particular, optimality can be characterized in terms of the game-theoretical notion of a `Nash Equilibrium'.