Interest has increased in examining the physical activity levels of young people during school recess. Identifying correlates of their recess physical activity behaviors is timely, and would inform school-based physical activity programming and intervention development. The review examined the correlates of children's and adolescent's physical activity during school recess periods. A systematic search of six electronic databases, reference lists, and personal archives identified 53 studies (47 focused on children) published between January 1990 and April 2011 that met the inclusion criteria. Data were analyzed in 2011. Correlates were categorized using the social-ecological framework. Forty-four variables were identified across the four levels of the social-ecological framework, although few correlates were studied repeatedly at each level. Positive associations were found of overall facility provision, unfixed equipment, and perceived encouragement with recess physical activity. Results revealed that boys were more active than girls. Providing access to school facilities, providing unfixed equipment, and identifying ways to promote encouragement for physical activity have the potential to inform strategies to increase physical activity levels during recess periods. Copyright © 2012 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.