Background/Objectives Sedentary behavior, physical activity and dietary behavior are formed early during childhood and tend to remain relatively stable into later life. No longitudinal studies have assessed the independent influence of these three energy balance-related behaviors during toddlerhood on later adiposity. We aimed to analyze the associations between screen time, outdoor play time, and dietary patterns at age 2 years and child adiposity at age 5, in boys and girls separately. Subjects/Methods This study included 883 children from the French EDEN mother-child cohort. Screen time, outdoor play time and dietary intakes were reported by parents in questionnaires when the child was aged 2. Two dietary patterns, labelled “Guidelines” and “Processed, fast-foods”, were identified in a previous study. Percentage of body fat (%BF) based on bioelectrical impedance analysis and body mass index were measured at age 5. Results In boys, screen time at age 2 was positively associated with %BF at age 5 (β= 0.51 (95% confidence interval (CI): 0.02, 1.01) for those boys with ≥60 min/day of screen time vs. those with ≤15 min/day, P for trend 0.045). In girls, outdoor play was inversely associated with %BF (β= -0.93 (95%CI: -1.58, -0.28) for those in the highest tertile of outdoor play time vs. those in the lowest tertile, P= 0.002). Overall, at age 2, dietary patterns were associated with both screen time and outdoor play time, but no significant and independent association was observed between dietary patterns and later adiposity. Conclusion This study shows longitudinal and gender differentiated relations between both screen time and outdoor play time in toddlerhood and later adiposity, while evidence for a relation between dietary patterns and subsequent fat development was less conclusive. Early childhood - by age 2 - should be targeted as a critical time for promoting healthy energy balance-related behaviors.