This research examined changes in intrinsic and extrinsic motivation during the transition from junior to senior high school as well as the impact of motivational changes on various educational consequences (i.e., dropout intentions, absenteeism, homework frequency, and educational aspirations). A total of 646 participants completed a questionnaire in 8th, 9th, and 10th grade. Using the true intraindividual change modeling technique (R. Steyer, I. Partchev, & M. J. Shanahan, 2000), the authors reached results revealing that students' intrinsic motivation and extrinsic motivation decreased gradually from 8th to 10th grade. Furthermore, less educational adjustment was observed for students experiencing a decline in external regulation during the transitional year and students experiencing a decline in intrinsic motivation and identified regulation during the year after the transition.