W hile researchers studying groups typically stay within their own setting (e.g., work, school, health, psychotherapy), much can be learned by stepping outside our traditional silos. For instance, sports and exercise are settings where groups are pervasive and individual and group outcomes are important. Members of a sports team who perceive that the team lacks cohesiveness may exert less effort, which may compromise skill development and the ability to win games.Researchers in sports and exercise settings have a history of examining group effects (Carron & Eys, 2012), and to be clear, some physical activity findings do migrate. The recognized tendency for individuals to exert less effort when working collectively versus individually (i.e., social loafing; Karau & Williams, 1993) originated with a sports task (tug-of-war). In addition, examination of the effect of present others on an individual's performance (social facilitation) came from the sports context of bike riding (Triplett, 1898). Yet, crossover of findings appears to be the exception rather than the rule.The intent of this chapter is to (a) present representative research examining select group constructs in sports and exercise settings; (b) use the findings from these studies as a heuristic to suggest possible future research directions in areas both inside and outside of sports and exercise, including therapy groups; and (c) provide suggestions for practitioners. The framework outlined by Marvin Shaw (1981) in his celebrated text Group Dynamics: The Psychology of Small Group Behavior underpins the constructs selected for this chapter.