Executive functions (EFs) develop rapidly in preschoolers and lay an important foundation for school readiness. One potential method of supporting EF development is through mindfulness-based interventions (MBIs). Whereas studies with older children and adults have supported this approach, research with young children has been more limited. In the current study, we evaluated the effectiveness, acceptability, and feasibility of "Mini-Mind," a 12-session MBI created specifically for preschoolers. We used a randomized controlled design in a sample of 27 (intervention n = 12) preschoolers (3-5 years old). The evaluation included indirect measures of EF skills completed by teachers who were blinded to the experimental condition of the students. Additionally, parents, teachers, children, and facilitators provided feedback about the acceptability and feasibility of the intervention. Findings revealed mostly nonsignificant, small-to-medium effects in favor of the intervention group on indirect measures of EF skills. Furthermore, "Mini-Mind" was rated as highly feasible and acceptable by children and stakeholders. Overall, the findings support the implementation and continued evaluation of "Mini-Mind" in more diverse settings.