The purpose of this study was to investigate the irrational beliefs in career choice of students who are considering the selection of careers in the fields of science, technology, engineering and mathematics (STEM) according to their gender, school type and academic achievement. In the Turkish educational system of career classification two areas predominate in the STEM areas: natural and physical science, and engineering, production and structure. The subjects of this study were 278 (126 female, 152 male) students from three high schools. Data were collected from respondents using Scale for Irrational Beliefs in Career Choices along with demographic information form. Two-way variance analyis results detected significant main effect differences between school and gender and an interaction effect for science grade point average for students planning to pursue natural and physical science. Similarly significant main effect differences were detected for gender and academic achievement and an interaction effect for overall grade point average was observed among the subjects who planned to pursue engineering production and structure preparation.