This chapter discusses to communication interventions that have been based on a theory of motivation, namely self-determination theory (SDT), to create satisfying experiences that motivate optimal engagement and facilitate health and performance in physical activity/exercise and sport settings. It offers illustrative examples of interventions guided by this theory in which motivationally-supportive communication styles in sport, exercise and physical education (PE) were applied. Need-supportive communication characterizes a coach, PE teacher, or exercise professional as the other's ally and support system rather than a "leader and persuader". Unlike most attempts to influence someone else's behavior, need-supportive communications are empathic, flexible, and patient, rather than taking-charge, pressuring, and urgent. Need-supportive communication creates conditions for people to motivate themselves in ways that are rich in volition and personal causation. When implementing such evaluations, it is important to be cognizant of the fact that communication training aims to upskill individuals to motivate those they interact with, in ways that are need-supportive and less need-thwarting.