In this study, it was aimed to evaluate the effects of Promoting Alternative Thinking Strategies (PATHS)--Preschool Curriculum on Preschool Children's Social Skills. The six years old children (N = 95) and their teachers (N =7) were included in participant group in Izmir. With a pretest-intervention-posttest design, data was collected through Promoting Alternative Thinking Strategies Preschool Evaluation Kit, Kusche Emotional Inventory, Head Start Competence Scale--Teacher Version, Teaching Style Rating Scale, Classroom Atmosphere Rating Scale. The evaluation findings indicated that (i) the training effects were large for increasing concentration and attention skills F(1,93) = 6.24*, p less than 0.05) and social emotional competence (F(1,93) = 11.69*, p less than 0.05; F(1,93) = 29.23**, p less than 0.001); (ii) reducing aggression and disruptive behaviors (F(1,93) = 7.06**, p less than 0.001); (iii) no significant intervention effects could be detected on any emotion knowledge skills (F(1,84) = 10.80). However, as compared to the control group, it was found that (iv) the intervention improved the level of children's compliance, cooperation, problem solving, feeling expression (F(1,93) = 29.23**, p less than 0.001.), and (v) the level of teachers' discipline strategies, emotional support, problem solving, and preventing misbehavior F(1,5) = 8.24*, p less than 0.05; F(1,5) = 30.42**, p less than 0.001; F(1,5) = 31.20**, p less than 0.001; F(1,5) = 35.07**, p less than 0.001). At the end of the study, it was found that PATHS--Preschool was an effective program in terms of improvement of children's social emotional competence and to lay groundwork for a comprehensive evaluation of the program as a preventive intervention for Turkish children.