Introduction: In the last decades, different studies have investigated the effects of exercise or physical activity (PA) on cognitive functions and academic performance in children and adolescents. But given the inconsistencies regarding methodologies and the fact that many studies do not have controlled or randomized designs, a more recent review is needed in order to summarize the different outcomes and methodologies employed and correlate them from an applied perspective. Objectives: The purpose of the present review is to systematically review and analyze the effects of acute and chronic PA interventions exclusively from randomized controlled trials (RCTs) on cognitive functions and academic performance of children and adolescents. Methods: A literature search was conducted using MEDLINE (via PubMed), EMBASE, Web of Science, and PsycINFO databases for all RCTs published between January 2014 and July 2020. Authors searched these databases using controlled vocabularies, keywords, and Boolean logic, and data were later extracted from the studies. Effect sizes were calculated based on means and SDs at posttest using Hedge's g formula. Results: A total of 20 studies met the inclusion criteria. They were assessed for eligibility and later included in the review. Although most of the articles did not show any robust effect size and had significant methodological differences, 80% of the studies analyzed showed positive results, indicating a significant impact of exercise or PA on cognition. Discussion: Due to the heterogeneity in the design of the interventions and the variables analyzed, most of the studies showed small or medium effect sizes. Studies with big effect size in all variables had in common the fact that they involved team game variations and coordination activities. The combination of physical exertion (high intensity) and cognitive engagement with social interactions seems to have the strongest effect on executive functions. This ecological and attractive model reflects children's typical PA and might represent an ideal model for exercise in this population. Conclusions: Although grouping different studies based on PA type, control groups, and comparison treatments is a limitation and results should be interpreted with caution, this review suggests that PA interventions, in particular, team game variations and coordination activities, have positive effects on children's cognitive functions. Keywords: Children; Cognition; Exercise; Physical activity.