Background: The scientific interest in high-intensity interval training (HIIT) has greatly increased during recent years. Objective: The objective of this meta-analysis was to determine the effectiveness of HIIT interventions on cardio-metabolic risk factors and aerobic capacity in overweight and obese youth, in comparison with other forms of exercise. Data sources: A computerized search was made using seven databases. Study eligibility criteria: The analysis was restricted to studies that examined the effect of HIIT interventions on cardio-metabolic and/or aerobic capacity in pediatric obesity (6–17 years old). Participants and interventions: Nine studies using HIIT interventions were selected (n = 274). Study appraisal and synthesis methods: Standarized mean difference (SMD) and 95% confidence intervals were calculated. The DerSimonian–Laird approach was used. Results: HIIT interventions (4–12 week duration) produced larger decreases in systolic blood pressure (SMD = 0.39; −3.63 mmHg) and greater increases in maximum oxygen uptake (SMD = 0.59; 1.92 ml/kg/min) than other forms of exercise. Also, type of comparison exercise group and duration of study were moderators. Conclusions: HIIT could be considered a more effective and time-efficient intervention for improving blood pressure and aerobic capacity levels in obese youth in comparison to other types of exercise.