Educational research is continously examining the changes and progress of students throughout their educational career. Understanding student change is a critical element in creating learning settings that can meet the diverse needs of students. An area of inquiry important to the education, engagement and learning of students is their motivation or self-determination. Researchers commonly make an inference that motivation decreases as student's progress throughout their academic career, yet no empirical evidence has been gathered to support these claims. Therefore, the purpose of this study was to examine the self-determined motivation toward physical education of three different groups of students. Data were collected using a cross-sectional longitudinal design, whereby 50 students each in grades 7, 9 and 11 were randomly selected for this study and completed a survey on motivation toward physical education. Results revealed that as students progressed throughout their career, their motivation toward physical education decreased.