The aim of this study is to develop a scale to determine the spatial thinking skills of secondary school students. The study group of the research consists of 700 5th, 6th, 7th and 8th grade students, who are educated in about 10 schools. During the development of the scale created within the scope of the social studies course curriculum, the relevant literature was scanned. A pool of 36 items was created within the framework of expert opinions, the number of items in the scale was reduced to 14 and a 5-point Likert-type draft scale was developed. The created STS (Spatial Thinking Skill) scale was piloted to 5 students separately from the study group, and some expressions that were not understood were arranged and finalized. As a result of the factor analyzes carried out to ensure the construct validity, it was seen that the STS scale consisted of 4 factors. The Cronbach Alpha coefficient was calculated to ensure the reliability of the scale, which was shaped as 14 items by factor analysis and 0.91 value was found. It can be said that the STS scale can be used in scientific research as a result of examining detailed expert opinions, examining the feedbacks from the study group, performing factor analyzes and revealing the validity/reliability coefficients. Using the STS scale developed in the current study, students' skill development can be examined from various perspectives.