Background: Although sleep has been identified as an important modifiable risk factor for injury, the effect of decreased sleep on sports injuries in adolescents is poorly studied. Purpose: To systematically review published literature to examine if a lack of sleep is associated with sports injuries in adolescents and to delineate the effects of chronic versus acute lack of sleep. Methods: PubMed and EMBASE databases were systematically searched for studies reporting statistics regarding the relationship between sleep and sports injury in adolescents aged <19 years published between 1/1/1997 and 12/21/2017. From included studies, the following information was extracted: bibliographic and demographic information, reported outcomes related to injury and sleep, and definitions of injury and decreased sleep. Additionally, a NOS (Newcastle-Ottawa Scale) assessment and an evaluation of the OCEM (Oxford Center for Evidence-Based Medicine) level of evidence for each study was conducted to assess each study’s individual risk of bias, and the risk of bias across all studies. Results: Of 907 identified articles, 7 met inclusion criteria. Five studies reported that adolescents who chronically slept poorly were at a significantly increased likelihood of experiencing a sports or musculoskeletal injury. Two studies reported on acute sleep behaviors. One reported a significant positive correlation between acutely poor sleep and injury, while the other study reported no significant correlation. In our random effects model, adolescents who chronically slept poorly were more likely to be injured than those who slept well (OR 1.58, 95% CI 1.05 to 2.37, p = 0.03). OCEM criteria assessment showed that all but one study (a case-series) were of 2b level of evidence—which is the highest level of evidence possible for studies which were not randomized control trials or systematic reviews. NOS assessment was conducted for all six cohort studies to investigate each study’s individual risk of bias. Five out of six of these studies received between 4 to 6 stars, categorizing them as having a moderate risk of bias. One study received 7 stars, categorizing it as having a low risk of bias. NOS assessment revealed that the most consistent source of bias was in ascertainment of exposure: all studies relied on self-reported data regarding sleep hours rather than a medical or lab record of sleep hours. Conclusions: Chronic lack of sleep in adolescents is associated with greater risk of sports and musculoskeletal injuries. Current evidence cannot yet definitively determine the effect of acute lack of sleep on injury rates. Our results thus suggest that adolescents who either chronically sleep less than 8 hours per night, or have frequent night time awakenings, are more likely to experience sports or musculoskeletal injuries.