Objectives: Determine both the effects and hierarchy of effectiveness for exercise interventions (aerobic, strength training or both) on selected measures of adiposity (body mass index (BMI) in kg/m2, fat mass and per cent body fat) in overweight and obese children and adolescents. Design: Network meta-analysis of randomised exercise intervention trials. Setting: Any setting where a randomised trial could be conducted. Participants: Overweight and obese male and/or female children and adolescents 2-18 years of age. Interventions: Randomised exercise intervention trials>4 weeks, published between 1 January 1973 and 22 August 2018, and which included direct and/or indirect evidence for aerobic, strength training or combined aerobic and strength training. Primary outcomes: Changes in BMI in kg/m2, fat mass and per cent body fat. Results: Fifty-seven studies representing 127 groups (73 exercise, 54 control) and 2792 participants (1667 exercise, 1125 control) met the criteria for inclusion. Length of training ([Formula: see text] ± SD) averaged 14.1±6.2 weeks, frequency, 3.3±1.1 days per week and duration 42.0±21.0 min per session. Significant and clinically important reductions in BMI, fat mass and per cent body fat were observed in aerobic versus control comparisons (BMI, mean, 95% CI -1.0, 1.4 to -0.6; fat mass -2.1, -3.3 to -1.0 kg; per cent fat -1.5, -2.2 to -0.9%) and combined aerobic and strength versus control comparisons (BMI -0.7, -1.4 to -0.1; fat mass -2.5, -4.1 to -1.0 kg; per cent fat, -2.2, -3.2 to -1.2%). A significant reduction in per cent fat was also found for strength vs control comparisons (-1.3,-2.5 to -0.1%). Combined aerobic and strength training was ranked first for improving both fat mass (kg) and per cent body fat while aerobic exercise was ranked first for improving BMI. Conclusions: Aerobic and combined aerobic and strength training are associated with improvements in adiposity outcomes in overweight and obese children and adolescents.