Not much evidence exists concerning the effects on sleep and mood of transcranial bright light. In this study, 50 students, all with wake-up time 9: 00 a.m. or later in weekends/free days, participated in a double-blind placebo-controlled experiment comparing the effects of bright light (n = 27; 8.0 lm) and placebo (n = 23; 0.1 lm). Data collection consisted of sleep assessment, with both sleep diaries and actigraphy. In addition, the Fatigue Severity Scale and the Profile of Mood States (POMS) were administered. Following 1 week of baseline recording, the therapy was initiated, aiming to phase advance the sleep-wake period. The therapy lasted for 2 weeks and consisted of gradually advancing daily light exposure of 12 min' transcranial bright light. Subjects in the two conditions did not change differently from baseline to post-treatment on any sleep parameters. A significant condition 9 time interaction was found for one of six subscales (vigor-activity) of the POMS, suggesting a more favorable development from baseline to post-treatment in the placebo compared to the bright light condition. No differences in terms of side-effects were reported between conditions. It is concluded that transcranial bright light, at times where conventional light therapy has phase-advancing properties, did not influence any sleep parameters differently than placebo. Transcranial bright light was associated with a less favorable development from baseline to post-treatment on one mood parameter compared to placebo.