The aim of this study was to evaluate the effectiveness of STEM Curriculum designed and implemented for undergraduate programs of faculties of education. The research model is experimental. The design is a single group pre-test post-test experimental design. The study group consisted of 18 pre-service teachers studying in the Department of Science Education. In order to determine the effectiveness of STEM Curriculum, two data collection tools were prepared: "Education Module Evaluation Form" and "Interview Form". The Wilcoxon Signed Ranks Test was used to analyze the quantitative data and the content analysis was used to analyze the qualitative data. According to the findings, it was concluded that the STEM curriculum applied positively influenced the development of the competency of pre-service teachers to prepare education module (lesson plans, work sheets, measurement-evaluation tools) according to STEM education approach. It was concluded that the STEM curriculum contributed to the knowledge and skills, professional competencies and awareness of preservice teachers about preparing educational material according to STEM education approach.