This study aimed to determine whether there were differences in student interest in Science, Technology, Engineering, Mathematics (STEM) careers based on grade level and the factors influencing it. A descriptive quantitative method was used with the distribution of questionnaires. Closed questionnaires (5 Likert scales) using the Science, Technology, Engineering, Mathematics-Career Interest Survey (STEM-CIS) model were distributed online through proportionate random sampling. This study involved 375 secondary school students majoring in natural science from public and private schools. Data analysis was performed using Statistical Package for the Social Sciences (SPSS) 25.0 software with the Kruskal Wallis test. The results showed a significance value (Sig.) = 0.146. There is no significant difference in students’ interest in Science, Technology, Engineering, Mathematics (STEM) careers. The differences can be seen in the average scores at each grade level, even though it was slight. The average grade 10 = 3.183, grade 11 = 3.157, and grade 12 = 3.015. Grade level is inversely related to students’ Science, Technology, Engineering, Mathematics (STEM) career interests. The higher the grade level, the lower the interest in Science, Technology, Engineering, Mathematics (STEM) careers. The influencing factors are self-efficacy, personal goals, the expectation of a result, interest, and individual input. This study supports that teachers need to apply certain strategies to students from the first-grade level by considering the influencing factors to increase Science, Technology, Engineering, Mathematics (STEM) career interest.