This article focuses on the research on interest, especially situational interest, in physical education. Interest has been considered a powerful motivator for children and adolescents. Based on a conceptualization of individual and situational interest, a reasonable size of evidence has been accumulated showing that situational interest motivates students to engage in physical activity. The evidence also shows that situational interest may have little impact on learning achievement. It, however, can be controlled and manipulated by teachers to create a situationally interesting learning environment to enhance engagement. The lack of studies on individual interest and its development has been identified as a void in this line of research. We argue that it is necessary to strengthen the research on individual interest and its interaction with situational interest to fully understand the four-phase theoretical model of interest development in the physical activity domain (Renninger & Hidi, 2016).