This study was conducted to investigate the effect of education based on Self-Regulation Strategy Development Model on the writing skills development of 6th grade (middle school) students. In this study, a pretest-post-test, quasi-experimental method with control group was used. The sample of the study consists of 60 students enrolled in two public middle schools affiliated with Aksaray Central Provincial Directorate of National Education. These two schools were determined as experimental and control groups randomly. The implementation of the study, which included two groups designated as experimental and control groups, was completed in 12 weeks, 2 lesson hours per week. In the collection and evaluation of the data, narrative and informative texts written by students, the Attitude Towards Writing Scale (ATWS), the Self-Regulated Writing Scale (SRWS) and the Ranked Scoring Key for the Evaluation of Written Expression (RSKEWE) were used. SPSS 24 program was used to analyze the data. As a result of the study, it was seen that the experimental group students' written expression skills, writing self-regulation skills and writing attitudes levels were significantly higher compared to the control group students'.