Sport stacking is an activity taught in many physical education programs. The activity, although very popular, has been studied minimally, and the energy expenditure for sport stacking is unknown. Therefore, the purposes of this study were to determine the energy expenditure of sport stacking in elementary school children and to compare that value to the energy expenditures of other activities often included in physical education curricula. Twenty five children (mean age = 11 [plus or minus] 1.6 years, 17 boys, 8 girls) had their expired gases analyzed via a metabolic cart for a 5-minute standing period to establish a baseline reading and for a 5-minute period while they were sport stacking. Energy expenditure was calculated as metabolic equivalents (METs). Repeated measures ANOVA was used to compare the mean METs between standing and stacking and between sex. Mean standing and stacking energy expenditures were significantly different. No significant differences were noted for mean energy expenditure by sex. The mean energy expenditure for sport stacking in elementary school children was 3.1 METs. The MET value for sport stacking is similar to other activities involved in typical physical education courses (e.g., bowling, dance, volleyball, weight lifting). (Contains 2 tables.)