Background Fatigue is a common symptom in people with multiple sclerosis (pwMS) that significantly impairs quality of life. Bright light therapy may be a cheap treatment option with little to no adverse events. Objectives To evaluate the effectiveness of bright light therapy as a treatment option for MS-related fatigue. Methods This was randomized sham-controlled trial including 26 pwMS with a Fatigue Severity Scale (FSS) Score ≥36. Participants were assigned to receive either bright white light therapy ( n = 13) or dim red light (sham-intervention; n = 13). Participants used the respective intervention for 30 min each morning for two weeks, followed by a two-week washout period. The primary endpoint was the difference in FSS scores following light treatment as calculated by analysis of covariance. Results There was no significant difference in FSS (F(1,23) = 2.39, p = .136, partial ⴄ2 = .094). However, FSS scores generally improved over the course of the study in a clinically relevant manner. Conclusion Bright light therapy decreased FSS scores over the course of this study. However, this effect was not significant in comparison to a sham intervention.