Autonomy has been considered both as a precondition and a crucial learning outcome of higher education. Recent research has been focusing on measuring university students' autonomy or its development. However, whether and how students' autonomy can be measured quantitatively is still debatable. Although autonomy is known as a changing process and varies among individuals, it is agreed that students' learning behaviours are largely affected by their perceptions; very few studies, however, have examined students' own perception of autonomy. This study, therefore, adopts a longitudinal qualitative approach to investigate the changes in students' own perceptions of autonomy over five different times during their first-year study in a Hong Kong University, and examine the relationship between the perceptions and behaviours of their autonomy. Using in-depth semi-structured interviews with eight first-year students, the study found that although the participants held some common understanding of autonomy, they also demonstrated various interpretations of this concept. They also had a slightly different focus on different dimensions of autonomy, which were affected by their own individual experiences. An individualistic approach is therefore proposed to understand students' development of autonomy.