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.05) and social emotional competence (F(1,93)= 11.69*, p.05; F(1,93)= 29.23**, p.001); (ii) reducing aggression and distruptive behaviors (F(1,93)= 7.06**, p.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.001.), and (v) the level of teachers' discipline strategies, emotional support, problem solving, and preventing misbehavior F(1,5)= 8.24*, p.05; F(1,5)= 30.42**, p.001; F(1,5)= 31.20**, p.001; F(1,5)= 35.07**, p.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. (author abstract)