Purpose: To determine the validity of standing long jump (SLJ) for predicting muscle power in children with and without developmental coordination disorder (DCD). Methods: A total of 589 children were recruited as part of the Coordination and Activity Tracking in CHildren study (251 girls and 338 boys; mean age 59.2 mo). Children were classified as typically developing (>16th percentile), at risk for DCD (sixth to 16th percentile), or probable DCD (<sixth percentile) based on Movement Assessment Battery for Children—Second Edition scores. SLJ was measured from the back of the heel. Peak power and mean power over 10 seconds and 30 seconds were measured using the Wingate test. Results: SLJ was moderately correlated with peak and mean powers in all groups (R = .51–.55). Regression analysis showed that when combined with weight and age, SLJ performance could predict peak power and mean power over 10 seconds and 30 seconds in typically developing children (adjusted R2 = .68, .61, and .58, P < .001, respectively) and in children with risk for DCD (adjusted R2 = .74, .65, and .60, respectively) and probable DCD (adjusted R2 = .68, .61, and .59, respectively). Conclusions: SLJ, in combination with weight and age, may be used to measure muscle power in typically developing children, and in children with risk for DCD and probable DCD. This measure can be used as an inexpensive estimate of musculoskeletal fitness in children regardless of motor abilities.