Background: Functionality appreciation, as an important aspect of positive image, is associated with fewer body image disturbances, fewer disordered eating behaviors, and improved psychological well-being. However, it has been under-researched in Asian countries. The current work aimed to examine the psychometric properties of the Functionality Appreciation Scale (FAS) among four Chinese samples of different ages, and further examine measurement invariance and differences of the FAS across gender and age groups. Methods: Exploratory and confirmatory factor analyses (EFA and CFA) were conducted to examine the factorial structure of the FAS among four Chinese samples of different ages, including middle school adolescents (n = 894, M = 12.17 years), high school adolescents (n = 1347, M = 15.07 years), young adults (n = 473, M = 21.95 years), and older adults (n = 313, M = 67.90 years). The measurement invariance of the FAS across gender and age was examined. Internal consistency reliability and construct validity were evaluated. Results: The FAS had a unidimensional structure and was invariant across gender and age groups. The FAS presented sound psychometric properties in all age groups by gender, with good internal consistency reliability [e.g., high Cronbach’s α values (.91 ~.97)] and good construct validity (e.g., significant associations with body appreciation, body dissatisfaction, and disordered eating). Moreover, group comparisons showed minimal gender differences in functionality appreciation. However, significant age differences were found in functionality appreciation, with older ages generally associated with higher functionality appreciation. Conclusion: Overall, findings suggest that the FAS is a sound instrument to be used in the Chinese context. Furthermore, functionality appreciation was found to be higher in older adults than adolescents or young adults, suggesting the potential important role of aging in functionality appreciation.