Objective: Genetic influences on post-concussion neurocognitive performance are not well understood, especially the relationship between genetics and intraindividual cognitive variability. The purpose of this study was to determine whether the e4 allele of the APOE gene impacts neurocognitive performance variability following concussion in a sample of college athletes. It was hypothesized that concussed athletes with an e4 allele would show greater performance variability than those without an e4 allele. Method: Participants were comprised of 60 concussed athletes (76.7% male) who participated in a concussion management program. All athletes underwent a comprehensive neuropsychological assessment and provided a DNA sample for determination of their APOE genotype. Two measures of variability were computed: a range score, calculated by taking the difference between each athlete's highest and lowest standard scores across the test battery and an average standard deviation (ASD) score across all tests. Results: The sample was divided into e4+ (n = 20) and e4- (n = 40) groups and no significant differences were found between the allele groups on demographic and injury severity characteristics. Independent samples t-tests showed no significant differences between athletes with and without the e4 allele on the range score (t(25) = -1.39, p = .176, d = 0.42), but e4+ athletes had a greater ASD score than e4- athletes (t(59) = -2.05, p < .05, d = 0.53). Conclusion: This research furthers our understanding of how genetic factors uniquely contribute to individual differences following concussion. Findings showed that when compared to e4- athletes, e4+ athletes demonstrated greater intraindividaul variability following concussion, suggesting that the e4 genotype may be a risk factor for less efficient cognitive processing in concussed athletes.