This study investigated students' conceptions of constructivist learning activities in a problem-based learning (PBL) and a traditional curriculum. We examined whether students who have chosen for a problem-based curriculum have different conceptions of constructivist assumptions compared to students who have chosen to be enrolled in a traditional, lecture-based curriculum when they enter university. 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 the hypothesized model in both student populations and to calculate latent means. Results suggested that students in the PBL environment agree more on constructivist assumptions of cooperative learning and the use of authentic problems, while students in the traditional curriculum acknowledge the importance of motivation to learn more. It is discussed that conceptions of constructivist learning activities can act as an important moderator of PBL effects and should be considered in examining the effects of PBL and probably in all comparative education research.