The high prevalence and the negative consequences of poor sleep during adolescence has led to an increasing interest on the role that protective and risk factors, such as mindfulness and rumination, play. Therefore, we aimed to examine whether the mindfulness profile predicted less sleep problems and whether rumination mediated this association. A sample of 304 adolescents (195 girls, Mage = 16.40, SD = 1.61) was assessed at three time points separated by two months. The adolescents completed measures of dispositional mindfulness, sleep problems, and ruminative responses. According to scores on mindfulness facets, a two-profile model emerged as the most adequate: one characterized by “non-judgmental awareness” and the other by “judgmental observation”. In mediational models “non-judgmental awareness” predicted reductions of rumination and sleep disturbances two- and four-months later respectively. Rumination at baseline predicted significant increases of sleep problems, latency, disturbances, and efficiency, while rumination at two-month follow-up predicted significant increases on the use of medication at four-month follow-up. Being “non-judgmentally aware” appears to protect against rumination and sleep problems such as the need of medication and the sensitivity towards disturbances. However, the way in which mindfulness profiles are related to sleep problems could be different for each specific aspect of sleep. Finally, implications of the study for the prevention and treatment of sleep problems are discussed.