As technology advances and offers enjoyable sedentary alternatives to sport, active recreation, and transportation, there is a growing need to understand and harness the drivers of physical activity and exercise among children and adolescents. Determining how youth perceive their physical capabilities and their opportunities and what motivates them to be physically active can provide essential information for teachers, coaches, youth leaders, and program planners who are interested in promoting physical activity. Several well-established and also more recently developed behavioral theories offer numerous avenues to gaining a better understanding of the perceptions and motivation of youth with respect to physical activity and exercise behavior, including the social ecological model, social cognitive theory, self-determination theory, habit theory, dual-process theory, and nudge theory, among others. Children and adolescents have individual characteristics that influence their perceptions, motivations, and behavior. They also exist within a multilayered ecological context that helps to shape those perceptions, motivations, and behavior. For youth to be sufficiently physically active and thereby help to reach their full potential, the environment must be conducive to consistent routines of physical activity. Such an environment can be designed to provide easily accessible and enjoyable opportunities for youth to fulfill their basic psychological needs for autonomy, relatedness, and competence to be physically active. There is potential for technology to contribute positively toward the design of conducive environments, and toward fostering motivation and enjoyment of exercise and physical activity among children and adolescents.