This study was conducted as part of the project Art of Happiness: Positive Thinking in Preschool and Subjective Well-Being Project, a preventive psycho-educational project. The research was planned as an action study, structured with four interrelated studies. The first study was conducted qualitatively with 15 teachers. First, the data regarding the expectations and requirements of teachers were obtained, the evaluation process was conducted, and positive thinking training was tailored for teachers. In the second study, the teacher training process, having been designed in line with the first study was implemented and tested. The study was conducted with a sample group comprising 50 experimental and 50 control groups, while a quasi-experimental design with a pretest-posttest control group was employed. The third study refers to the planning and designing of the education intended for children in schools for positive thinking and well-being practices. In this context, a focus group discussion was held through the involvement of eight teachers. In the fourth study, the implementation process in schools was evaluated. This study included 80 children aged 5, 40 of whom were in the experimental group and 40 in the control group. The effect of positive thinking education delivered to children was evaluated through the pretest-posttest control group design. Also, the process evaluations of the teachers who educated the children in the experimental group were obtained through interviews. Educational programs for teachers and children were developed and implemented within the scope of the study, and significant findings were obtained for both preschool teachers and children. Besides positive thinking training, research findings indicated that planning the process through the active participation of teachers and their embracing the project contributed significantly to the meaningful learning outcomes.
