There are very few studies examining the effects of sports-related concussion (SRC) on objective measures of school performance, such as grades or test scores. In this research, the grade point averages (GPAs) and scores of the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) of athletes who sustained an SRC during the school year were compared with those of athletes who did not have an SRC. Multivariate analysis of variance (MANOVA) revealed a significant linear decline in GPA of both groups across the school year, but indicated no difference in the GPA decline between the concussion and no concussion groups. The GPAs of the concussion and no concussion groups were not significantly different across the school year. Finally, no differences were found between the pre- and post-concussion ImPACT scores of the concussed athletes. This study found that an SRC during the school year did not affect the academic performance or neurocognitive test scores of high school athletes.