The current study tested predictions that well-being and mindfulness are positively associated with sleep quality and with a morning circadian preference. A model was also tested wherein mindfulness directly predicts well-being and indirectly predicts well-being through improved sleep quality. Results from a sample of 305 undergraduates revealed positive associations among measures of emotional, psychological, and social well-being, mindfulness, sleep quality, and morningness. A path analysis yielded support for mindfulness as a direct predictor of well-being and for mindfulness as an indirect predictor of well-being, mediated by sleep quality. Results are considered in terms of additional plausible relationships between mental health and sleep, and in terms of suggestions for future work.