Context: It is important to identify factors that increase injury risk among youth sport participants, as injury and the fear of injury can prompt athletes to dropout of sport. Several cross-sectional studies found that sport specialization is associated with increased injury rates, specifically overuse injury, among youth sport participants. However, there is a need to critically appraise high-quality pieces of prospective evidence linking sport specialization to injury to guide clinical recommendations for clinicians interacting with youth athletes. Clinical Question: Is sport specialization a risk factor for injury, specifically overuse injury, among youth athletes, based on evidence from studies using a prospective design? Clinical Bottom Line: Sport specialization appears to be a risk factor for overuse injuries among youth athletes across a variety of sports. Overuse injuries require more time to accurately diagnose and can result in lengthy and oftentimes recurring rehabilitation, ultimately placing more burden on the athlete and clinician. Athletic trainers are in a unique position that allows them to interact with youth sport stakeholders such as athletes, parents, and coaches, and may be the best candidate to provide education about safe youth sport participation behaviors.