OBJECTIVE: To compare before- and after-school neurocognitive performance and total symptoms in a sample of nonconcussed high school athletes. DESIGN: Repeated-measures, counterbalanced design. SETTING: Midwest high schools. PARTICIPANTS: Thirty-nine nonconcussed high school athletes. INTERVENTIONS: The Immediate Post-Concussion Assessment and Cognitive Testing battery was administered before and after school in a counterbalanced testing order. MAIN OUTCOME MEASURES: Neurocognitive and total symptom scores. RESULTS: Paired-sample t tests revealed no significant differences in verbal memory (P = 0.43), visual memory (P = 0.44), processing speed (P = 0.94), reaction time (P = 0.16), or total symptoms (P = 0.52) between before- and after-school testing sessions. CONCLUSIONS: The results of this study expand on best practice guidelines for baseline and postinjury concussion computerized neurocognitive testing and symptom report administration. This study suggests that sports medicine professionals can administer computerized neurocognitive testing before or after school without concern of confounding factors affecting performance or total symptoms.