Risky outdoor play has been associated with promoting children's health and development, but also with injury and death. Risky outdoor play has diminished over time, concurrent with increasing concerns regarding child safety and emphasis on injury prevention. We sought to conduct a systematic review to examine the relationship between risky outdoor play and health in children, in order to inform the debate regarding its benefits and harms. We identified and evaluated 21 relevant papers for quality using the GRADE framework. Included articles addressed the effect on health indicators and behaviours from three types of risky play, as well as risky play supportive environments. The systematic review revealed overall positive effects of risky outdoor play on a variety of health indicators and behaviours, most commonly physical activity, but also social health and behaviours, injuries, and aggression. The review indicated the need for additional "good quality" studies; however, we note that even in the face of the generally exclusionary systematic review process, our findings support the promotion of risky outdoor play for healthy child development. These positive results with the marked reduction in risky outdoor play opportunities in recent generations indicate the need to encourage action to support children's risky outdoor play opportunities. Policy and practice precedents and recommendations for action are discussed.