The aims of the study were to investigate the impact of The 101s parent training program: the nationally honored program in the US for promoting a child’s brain and social-emotional development with positive discipline, on Thai parenting skills and preschoolers’ executive function (EF) skills. The sample was 27 parents and their 3-5-year-old preschoolers in the intervention group in which the parents received the 101s training program and 27 parents and their 3-5-year-old preschoolers in the control group in which the parents received no training. A series of MANCOVA was performed to compare the significant differences in mean scores on parenting practices and EF skills between the sample in the intervention and control groups. A bivariate correlation was also utilized to evaluate the significant correlations between the parenting practices and preschoolers’ EF skills. The findings showed the significantly positive impact of the 101s parent training program on the parenting practices and preschoolers’ EF skills. The implication, limitations, and suggestions are discussed.