This study focused on the transition from upper-secondary school to university. Specifically, it examined whether prior academic achievements and conceptions of learning at the time of completion of upper-secondary school predicted short- and long-term university success (grades at the bachelor's and master's levels). A total of 171 psychology students (M[subscript age] = 23.99) participated in this retrospective longitudinal study. At the end of upper-secondary school, they completed the self-report instrument Learning Conceptions Questionnaire. Subsequently, their upper-secondary school-leaving certificate grades and grades at the bachelor's and master's degree levels were retrieved from their university database. The analytic results of Generalized Estimating Equations (GEE) revealed that upper-secondary school-leaving certificate grades and grades at the bachelor's and master's degree were significantly associated with each other. Furthermore, the conception of learning as 'Opportunities and self-efficacy' significantly predicted both upper-secondary school-leaving certificate grades and grades in bachelor's and master's degrees. Upper-secondary school students' conception of learning was linked to psychological engagement and personal agency, as well as high school-leaving certificate grades increasing the likelihood of attaining successful university performance.