Joint action is an increasingly popular topic in Cognitive Science. This popularity reflects a recent theoretical trend of postulating, in one way or another, that human perception, action, and cognition are geared to enable successful coordination and communica¬tion with others. The speakers in the symposium will provide an overview of current progress in joint action research. Their contributions will address a wide range of phenomena ranging from tight temporal coordination to shared planning and discourse processes. Together, the contributions will illustrate that social constraints affect cognitive processing in a deeper sense than the more traditional notion of specific modules for social perception and social reasoning would suggest.