According to a report by the Turkish Industry and Business Association, Turkey will need approximately 1 million individuals to be employed in Science Technology Engineering Mathematics (STEM) fields by 2023, and 31% of this requirement will not be met. For continuous economic development, there is a need to integrate STEM into education in Turkey, which brings the need for research in this area. This study, based on a survey model, aimed to determine the level of interest of a sample of Turkish middle school students in STEM careers on the basis of gender, where they lived, grade levels, their end-of-semester grades, and their parents' educational status and levels of income. The research data was collected using the STEM Career Interest Survey (STEM-CIS) and Personal Information Form, which were applied to 851 middle school students (fifth and eighth graders). The collected data was analyzed with SPSS using Mann Whitney U and Kruskal Wallis H tests. It was found that middle school students' interest in STEM careers differed according to sex, where they lived, and grade levels but it did not differ in relation to their parents' educational status and the levels of income of the family. It is believed that the results obtained in this study reflecting the profile in Turkey will guide educational policy makers, curriculum developers, teachers, pre-service teachers, and researchers about STEM education.