Past studies have supported the view that parent background and family socioeconomic status determine the post-secondary educational expectations of adolescents. They build on Pierre Bourdieu's social reproduction theory, but do not fully explain why some adolescents aspire to post-secondary education and some do not. The capability approach adopted by Amartya Sen, uses the concept of agency to address such individual differences and 'capability to aspire' may explain educational transitions. The data for this study is drawn from PISA 2012 and its longitudinal extension study of adolescents in Hong Kong. Results of logistic regression analyses suggest that the reproduction effects through school socioeconomic composition and habitus pertaining to parental expectation are major factors shaping adolescents' expectations of pursuing a bachelor degree. However, agency factors, that is adolescents' own capabilities, after taking into account their differing family socioeconomic backgrounds, can strengthen their aspirations to pursue a bachelor degree. This combined approach and its implications for theory and practice, as well as the limitations of the study, are discussed.