In this study, a mixed-method design was employed to investigate the association between a student-centred, problem-based learning (PBL) method and law students' motivation. Self-determination theory (SDT) states that autonomous motivation, which is associated with higher academic performance, can be reached when there is fulfillment of three psychological needs: autonomy, competence and relatedness. PBL aims to trigger autonomous motivation. In Study 1, 85 PBL law students (37% male; Mean age = 21.99 years) and 69 law students of a lecture-based, non-PBL program (39% male; Mean age = 22.72 years) filled out the Self-Regulation Questionnaire and an adapted version of the Work-related Basic Need Satisfaction Scale in order to measure autonomous and controlled motivation and perceived autonomy, competence and relatedness. In order to compare both groups, two MANOVAs were conducted and results showed differences neither in autonomous and controlled motivation, nor in feelings of autonomy and competence. However, PBL students experienced more relatedness. Additionally, in Study 2, focus-group discussions that were conducted indicated that PBL contains both autonomy-supportive and controlling elements, which might explain why no differences were found in perceptions of autonomy and autonomous and controlled motivation between PBL and non-PBL students. Furthermore, students reported that tutorial groups in PBL contributed to feelings of relatedness.