This study extends previous research investigating the effects of state-wide exit exams by studying the change from a class-based to a state-wide exit exam system over 5 years, using multilevel analyses and examining mediating effects of teachers’ practices on students’ motivational orientations. In this multi-cohort study, we analyzed in particular the effects on students’ interest, scholastic self-efficacy, and persistence in advanced level English courses (N = 1835) and mathematics courses (N = 1336) in two states in Germany (28 schools). Descriptive analyses, multivariate hierarchical regression analyses, and differences-in-differences analyses were carried out. The results revealed long-term effects of the implementation of state-wide exit exams particularly in the advanced level English courses. Here, a close relationship between the change in all analyzed motivational orientations and teacher support perceived by the students can be identified. These results show the ambivalent effects of state-wide exit exams: Due to the increased teacher competence support, students’ interest is enhanced in the long term. However, scholastic self-efficacy and persistence might have been negatively affected by state-wide exams, if teacher competence support had not increased over time. In the advanced level mathematics courses, the results are mixed. Implications for further research are discussed.