Virtual environments, such as online games and web-based chat rooms, increasingly allow us to alter our digital self-representations dramatically and easily. But as we change our self-representations, do our self-representations change our behavior in turn? In 2 experimental studies, we explore the hypothesis that an individual’s behavior conforms to their digital self-representation independent of how others perceive them—a process we term the Proteus Effect. In the first study, participants assigned to more attractive avatars in immersive virtual environments were more intimate with confederates in a self-disclosure and interpersonal distance task than participants assigned to less attractive avatars. In our second study, participants assigned taller avatars behaved more confidently in a negotiation task than participants assigned shorter avatars. We discuss the implications of the Proteus Effect with regards to social interactions in online environments.