OBJECTIVE: To determine the relationship between sleep quantity and sleep disturbances on symptoms and neurocognitive ability at the acute phase (<7 days) and post-sports-related concussion (SRC; >21 days). DESIGN: Prospective inception cohort study SETTING: General community setting of regional middle and high schools. PARTICIPANTS: Sample included 528 youth athletes with SRC and 443 controls ages 10-18. MAIN OUTCOME MEASURES: Athletes completed the Immediate Post-Concussive Assessment and Cognitive Testing (ImPACT) battery. Partial correlation analyses and independent t-tests were conducted to assess sleep quantity the night before testing. Multivariate analysis of covariance was used to assess sleep disturbances and its interaction with age. RESULTS: Less sleep quantity was correlated with greater report of cognitive (p = 0.001) and neuropsychological (p = 0.024) symptoms specific for prolonged recovery from SRC. Sleep disturbances significantly impacting each migraine, cognitive, and neuropsychological symptoms (p < 0.001). A significant interaction was found between sleep disturbances and age (p = 0.04) at >21 days post-SRC. CONCLUSIONS: Findings emphasize that continued presence of low sleep quantity and sleep disturbances in youth athletes with SRC should be a specific indicator to health professionals that these athletes are at an increased risk for protracted recovery. Further research should identify additional factors that may interact with sleep to increase risk of protracted recovery.