The aim of this study was to identify potential correlates of objectively measured physical activity in a sample of obese children. A cross-sectional design was used to assess 137 5–9-year-old obese children (mean ± s.d. age = 8.3 ± 1.1 years; mean BMI z-score = 2.76 ± 0.70; 58% girls) from two regional cities in New South Wales, Australia, before commencement in a treatment trial. Correlates examined included age, BMI z, parental BMI, perceived competence, health-related quality of life, daily minutes spent in small screen recreation (SSR), and fundamental motor skill (FMS) proficiency. Physical activity was assessed using accelerometers and values were calculated for % of monitored time spent in moderate- (MPA) and vigorous (VPA)-intensity physical activity and mean counts per minute (CPM). Analyses were conducted separately for boys and girls. Motor skill proficiency was significantly correlated with a number of physical activity variables for boys and girls. For boys, regression analysis revealed object-control proficiency predicted CPM (R² = 0.25) and age was a predictor of %MPA (R² = 0.56). Age and object-control skill proficiency were salient predictors of %VPA (R² = 0.34). For girls, age and daily minutes of SSR were the only significant predictors for CPM (R² = 0.13). Age was the sole predictor of %MPA (R² = 0.38) and %VPA (R² = 0.15). The targeting of FMSs at an early age should be tested in experimental studies as potential strategies to increase physical activity among obese children, particularly for boys. Interventions aimed at reducing sedentary behaviors among obese girls should also be considered.