The evidence regarding the effectiveness of STEM support programs for K-12 students to spark their interest in the STEM field is mixed. The goals and contents of support programs vary and mostly cover short intervention periods. So far, not many studies exist that cover different learning characteristics of students in long-term STEM support programs. Against this backdrop, the present paper engages in intra- and intergroup comparisons, characterizing groups of students interested in STEM who participated in three long-term STEM support programs and a control group. The sample contained a total of N = 1170 students. For this purpose, the study was divided into a description of the samples, an analysis of the factors influencing career choice decisions, and an analysis of the interest profiles of students in support programs based on a circumplex model comparing STEM and non-STEM students. The results of this study indicate that female students in different support programs tend to fall into the Ideas domain on Prediger's axis, and male students in support programs are located close to male students in the control group. Overall, the results align with the state of research, suggesting that support programs should be offered regularly, integrated into school curriculums, and linked with STEM universities and mentoring. This study indicates that future research in the context of STEM support programs could verify the effects on students' vocational interests with longitudinal analyses.