This chapter aims to demonstrate how Psychological Reactance Theory (PRT) could inform future research aimed at furthering understanding the role of persuasion within the contexts of sport and exercise. It focuses on the application of PRT to the study of sport, exercise, and physical activity. PRT provides a theoretical account for how individuals respond to a threatened or eliminated freedom. Four components are essential to understanding PRT: freedom, freedom threat, psychological reactance, and freedom restoration. The foundational premise of PRT rests on the notion of freedoms, which are beliefs that individuals hold about the ways in which they may act. Given that individuals perceive specific freedoms, anything that makes enacting a particular freedom more difficult can constitute a freedom threat. Psychological reactance is defined as "the motivational state that is hypothesized to occur when a freedom is eliminated or threatened with elimination".