Context: Fast visuomotor reaction time (VMRT), the time required to recognize and respond to sequentially appearing visual stimuli, allows an athlete to successfully respond to stimuli during sports participation, while slower VMRT has been associated with increased injury risk. Light-based systems are capable of measuring both upper- and lower-extremity VMRT; however, the reliability of these assessments are not known. Objective: To determine the reliability of an upper- and lower-extremity VMRT task using a light-based trainer system. Design: Reliability study. Setting: Laboratory. Patients (or Other Participants): Twenty participants with no history of injury in the last 12 months. Methods: Participants reported to the laboratory on 2 separate testing sessions separated by 1 week. For both tasks, participants were instructed to extinguish a random sequence of illuminated light-emitting diode disks, which appeared one at a time as quickly as possible. Participants were provided a series of practice trials before completing the test trials. VMRT was calculated as the time in seconds between target hits, where higher VMRT represented slower reaction time. Main Outcome Measures: Separate intraclass correlation coefficients (ICCs) with corresponding 95% confidence intervals (CIs) were calculated to determine test–retest reliability for each task. The SEM and minimal detectable change values were determined to examine clinical applicability. Results: The right limb lower-extremity reliability was excellent (ICC2,1 = .92; 95% CI, .81–.97). Both the left limb (ICC2,1 = .80; 95% CI, .56–.92) and upper-extremity task (ICC2,1 = .86; 95% CI, .65–.95) had good reliability. Conclusions: Both VMRT tasks had clinically acceptable reliability in a healthy, active population. Future research should explore further applications of these tests as an outcome measure following rehabilitation for health conditions with known VMRT deficits.