STEM education has benefits for students, such as increasing achievement and improving attitudes, motivation, interest toward STEM disciplines, and higher-order thinking skills. Teachers' characteristics, perceptions, and attitudes related to STEM influence teachers' implementation of integrative STEM approaches and, as a result, shape the learning environment. This study examined 513 pre-service teachers' attitudes towards STEM in terms of multiple variables (department, class level, gender, having a traineeship, or information about STEM) and investigates the relationship between participants' attitudes and academic grade point averages. Participants were pre-service preschool, classroom, science, and mathematics teachers that can be considered the basis of the STEM pipeline. Data were collected via a survey and were analyzed using descriptive statistics, t-test, ANOVA, and Pearson product-moment correlation. Results show that pre-service science teachers, senior pre-service teachers, and participants who had information or a traineeship about STEM had more positive attitudes towards STEM. There was no relationship between attitudes and grade points. It was also seen that the attitudes towards engineering-technology explain the most variance in the attitudes towards STEM. Therefore, the teacher preparation programs should give more attention to integrate the courses of science, technology, engineering, and mathematics and help the pre-service teachers (regardless of their departments) to realize the connectedness of STEM subjects.