In this study, it is aimed to develop a scale to be used to determine the STEM career interest of high school students. Because, when STEM career studies in the literature are examined, the lack of STEM career scale for high school students is remarkable. In this research, developing STEM Career Interest Scale for high school students is important for literature. The scale development principles specified by DeVellis were taken into consideration during the development of the scale. 25-items STEM career interest scale trial form was applied to 462 high school students in their 2016-2017 academic year in Kayseri in Turkey. Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) was performed for the construct validity through the data set obtained from the study group. SPSS 22 and AMOS 24 package programs were used to analyze the data. According to the results of Exploratory Factor Analysis (EFA), it was determined that the scale consisted of 20 items and 3 sub-dimensions. Scale sub-dimensions were named as: interest, self-efficacy, outcome expectations. It was determined that the three-factor structure related to the scale explained 71% of the total variance. The Cronbach alpha coefficient was 0.96 for the whole scale. STEM Career Interest Scale developed for high school students can be used in experimental studies or descriptive studies. Validity and reliability studies can be performed by applying the scale to different education levels and it can be used in the studies. [This study was presented as an oral presentation at the 10th International Congress of Educational Research in 2018.]