Purpose: We investigated the effects of classroom-based physical activity (CBPA) interventions on academic performance and assessed the impact of different CBPA elements on academic performance. Methods: Relevant experimental studies in four databases were searched from their inception to September 2022. Random effects models were used to compute standardized mean differences (SMDs) and 95% confidence intervals. Results: A total of 13 studies were included. CBPA interventions could improve academic performance in children and adolescents (SMD = 0.17, p = 0.02). For the CBPA elements, low frequency (no more than three times per week; SMD = 0.19, p = 0.01), moderate intensity (SMD = 0.19, p = 0.01), long time (more than 20 min in each intervention; SMD = 0.14, p = 0.05), integrated physical activity (SMD = 0.18, p = 0.04), no more than 400 metabolic equivalents of energy-min/week (SMD = 0.33, p = .001), and more than 8-week interventions (SMD = 0.19, p = 0.04) tended to improve academic performance. Conclusions: CBPA may improve academic performance in children and adolescents. CBPA elements also have an impact on academic performance.