Objective: To evaluate the effectiveness of Koru, a mindfulness training program for college students and other emerging adults. Participants: Ninety students (66% female, 62% white, 71% graduate students) participated between Fall 2012 and Spring 2013. Methods: Randomized controlled trial. It was hypothesized that Koru, compared with a wait-list control group, would reduce perceived stress and sleep problems, and increase mindfulness, self-compassion, and gratitude. Results: As hypothesized, results showed significant Group (Koru, Wait-List) × Time (Pre, Post) interactions for improvements in perceived stress (F[1, 76.40] = 4.50, p =0.037, d =0.45), sleep problems (F [1, 79.49] = 4.71, p =0.033, d =0.52), mindfulness (F [1, 79.09] = 26.80, p <0.001, d =0.95), and self-compassion (F[1, 74.77] = 18.08, p <0.001, d =0.75). All significant effects were replicated in the wait-list group. Significant correlations were observed among changes in perceived stress, sleep problems, mindfulness, and self-compassion. Conclusions: Results support the effectiveness of the Koru program for emerging adults in the university setting.