This study examines how design-based STEM (Science, Technology, Engineering and Mathematics) activities in early childhood affect the development of science process skills of 60-72-month-old children attending preschool education. The study was conducted using a participatory action research design and the participants of the study consisted of fifteen students studying in preschool education. The study participants were selected according to the convenience sampling method from purposive sampling methods. The Science Process Skills Graded Scale and photographs were data collection tools. With this graded scale students' weekly activities based on STEM activities were evaluated and their progress was monitored. This process was supported and revealed with photographs. The research was conducted by applying eight STEM scenarios designed based on the 5E learning model. The students' work was scored by two different raters and the data were analysed using descriptive statistics. It was determined that science process skills were inadequate in the first week, but a significant improvement was observed in these skills during the implementation process. The results of the research show that students enjoyed STEM applications, their interest levels increased, and their science process skills improved. Based on the results of the research, various suggestions were presented.

STEM, early childhood education, science education, science process skills, action research