Objectives There is a dearth of studies on the social validity of mindfulness-based school programs because the primary emphasis has been on effectiveness or efficacy of the programs in terms of academic engagement and performance, and classroom behavior of the students. The aim of the present study was to assess secondary outcomes of a mindfulness-based preschool program in terms of parental social validity. Methods Forty parents whose children were in a larger study that evaluated the feasibility and acceptability of the OpenMind-Korea (OM-K) preschool program participated. At the end of the school year, these parents completed a 7-item social validity rating scale on the social significance of the OM-K program. Results The majority of the parents rated the OM-K program as being socially valid. They noted that their children learned skills that they could use both at home and in the preschool, and that they would recommend this program to other parents. The parents rated the program as simple to use, acceptable, effective, and without unintended adverse effects. Conclusions Overall mean parent ratings of the social validity of the OM-K program were high and congruent with overall mean teacher feasibility and acceptability ratings.