Self-directed learning (SDL), is an essential concept in problem-based learning (PBL), and, in a broader sense, student-centred learning. Considering the complex nature of SDL, it has been taken for granted and given a shallow meaning, i.e. self-study. In order to develop a deeper understanding and make use of the potential in SDL, this paper discusses and puts forward a more profound meaning. The importance of regarding becoming a self-directed learner as a learning process, and the need for teachers to take part in the learning, is crucial. Two "thinking models", one concerning the PBL tutorial work and one the relationship between tutorial work and self-study, are introduced. The unifying idea behind the reasoning is to emphasise the essence of providing opportunities for, as well as stimulating, the students' inquiring approach and responsibility. (Contains 10 figures and 2 notes.)