The introduction of the International Classification of Functioning, Disability and Health has placed emphasis on framing health behavior as a multidimensional construct. In relation to childhood physical activity, this encompasses dimensions of functional performance, activity attendance, and subjective perceptions of involvement and enjoyment within activity settings. Current literature, however, primarily investigates physical activity in terms of performance and activity levels. The resulting misalignment of theory and measurement practice challenges the development of a comprehensive understanding of childhood physical activity behavior. For children with disabilities, who may have nuanced experiences in activity, there may be greater necessity to examine additional dimensions of physical activity (e.g., participation). In an effort to support meaningful interpretations of physical activity behavior measures among children with disabilities, the purposes of this article are to (a) conceptualize childhood physical activity within the International Classification of Functioning, Disability and Health, and (b) provide guidance on aligning measurement tools with physical activity dimensions.