 To determine the efficacy of bright white light exposure compared to dim red light exposure in reducing post-TBI fatigue, an 8-week, randomized parallel-group clinical trial will be performed. Outcome assessment will be blinded. Participants will complete a baseline battery T1 including 72 hours of actigraphy. Participants will then be randomized to either the Bright White Light BWL or the Dim Red Light DRL group. After 4 weeks of daily, 30-minute light treatments, the baseline battery will be re-administered T2 along with 3 more days of Actigraphy. A follow-up assessment involving the same measures will be administered 1 month-post cessation of light therapy T3. Participant treatment allocations will be masked for research team members conducting outcome measures. Secondary outcome measures will be administered to explore the effects of light therapy on mood, daytime sleepiness, sleep quality, circadian rhythms, anxiety, cognition and life satisfaction. 