Mindfulness has been gaining greater support and interest from researchers, clinicians, and educators in the last two decades. However, the effects of mindfulness practice among children are still understudied. Effects of mindfulness practice on self-regulation of attention and emotions were assessed among 242 students in the 2nd, 4th, and 6th grades in a school that has integrated mindfulness practice as part of the school experience, and in a comparison school. Self-regulation of attention was assessed by using CPT and Stroop tasks. Mindfulness levels, anxiety, and affective experience self-reports were also collected. The results indicate that mindfulness practice was associated with earlier development of self-regulation among students in the mindful school, as reflected by a significantly lower proportion of commissions in the CPT task, and a marginally significant higher proportion of correct trials in the Stroop task, at 4th grade in the mindful school as compared to the comparison school. Research regarding early implementation of mindfulness and its effects on developmental trajectories is warranted. The feasibility and efficiency of mindfulness practice as a social emotional learning technique, suggested by this study, warrants further research into the early implementation of mindfulness and its effects on the development of trait mindfulness as part of children’s daily life. Furthermore, we show that mindfulness can be incorporated in significant ways within the public curriculum and does not necessarily have to be some elite practice reserved for children of alternative parents.