Functionality appreciation describes the extent to which an individual appreciates, respects, and honors their body for what it can do. Functionality appreciation is a core component of the multidimensional positive body image construct and is relevant in the context of yoga (e.g., yoga is an embodying activity that can direct practitioners’ focus towards appreciating their body functionality and minimizing the importance of appearance). Alleva, Tylka, and Kroon Van Diest (Body Image, 23, 28–44, 2017) created the Functionality Appreciation Scale (FAS) to assess functionality appreciation. This chapter describes the development of the FAS, and the other studies that have investigated the FAS across different languages, geographical regions, and social identities. Collectively, this research shows that the FAS is a psychometrically sound measure, and that functionality appreciation is positively associated with aspects of positive body image and well-being, and is inversely associated with aspects of negative body image and ill-being. To date, one study has included the FAS within the context of yoga, and showed that Hatha yoga on its own may not lead to improvements in functionality appreciation. Future research on functionality appreciation using different research designs (e.g., experimental, longitudinal) and within the context of yoga will be valuable, and the FAS can facilitate this.