Mindfulness involves being present, aware, and non-judgmental. The present study investigates the efficacy of a brief weekly mindfulness intervention within the college classroom as a means of increasing psychological well-being among students. We hypothesized that mindfulness would have emotional, cognitive, and social benefits, and that students who participated more frequently would benefit more. Across six 10-week classes, N=800 university psychology students participated in a five-minute weekly mindfulness activity. Students completed measures of emotional, cognitive, and social functioning in both the first and last weeks as well as some questions specific to the mindfulness activities. We found strong support for our hypotheses for emotional and cognitive benefits. Emotional benefits included increased happiness, resilience, and significantly lower anxiety. Cognitive benefits included engagement in the activities, engagement in the class, being more focused in class, and a positive impact on grades. Students who participated more frequently and to a greater degree saw more positive effects from the intervention. We conclude that a brief mindfulness intervention may be an effective way to improve wellness on the university campus.