As mindfulness practices become more widely implemented in schools, they are attracting both keen interest and strong criticism. It is important that mindfulness-based programs adhere to sound child development principles, be aligned with the neuroscience of stress, be integrated in a holistic manner by teachers throughout the school day, and support the ethical application of "right-minded" values toward increasingly self-determined and equitable classrooms. This article describes the priorities, mechanisms of change, and practical strategies for realizing these ideals in the classroom. The project described is the first to experimentally test the Calm Classroom© (Luster Learning Institute) program, and has also enhanced it for the primary grades in order to evaluate the effectiveness of mindfulness and related practices in supporting students.