Mindfulness meditation has a long-standing history in Eastern practices that has received considerable public interest in recent decades. Indeed, the science, practice, and implementation of mindfulness-based interventions (MBIs) have dramatically increased in recent years. At its base, mindfulness is a natural human state in which an individual experiences and attends to the present moment. Interventions have been developed to train individuals how to incorporate this practice into daily life. In this article, the authors discuss the concept of mindfulness and describe its implementation in the treatment of psychiatric disorders. They further identify for whom MBIs have been shown to be efficacious and provide an up-to-date summary of how these interventions work, including research support for the cognitive, psychological, and neural mechanisms that lead to psychiatric improvements. This review provides a basis for incorporating these interventions into treatment.