This study investigated the impact of students' conceptions of constructivist learning activities on academic achievement and drop-out. Although constructivism represents an influential view of learning, studies investigating how students conceptualize this perspective have not been conducted before. A structural equation modelling approach was adopted to test different models relating students' conceptions to their achievement in the university setting. Results suggested an indirect relationship between conceptions and achievement, mediated by actual learning activities. What students believe about the role of knowledge construction in learning predicts the actual learning activities they undertake. How important they consider inability to learn and motivation for learning predicts their study time. (Contains 5 tables and 2 figures.)