Peer tutors' behaviour has been stated to have the power to create and increase learning opportunities within peer tutoring programs. However, previous studies have shown that peer tutors struggle to adopt facilitative and constructivist-oriented strategies, as they lean more towards directive and knowledge-telling strategies. This study aims to explore a typology of approaches to peer tutoring by unraveling peer tutors' behavioural strategies and related approaches. Furthermore, it aims to grasp peer tutors' behavioural repertoire in-depth by shedding light on the concerns and challenges they experience while tutoring. Results showed that peer tutors used a variety of strategies but were mainly inclined to adopt answering and directive actions. Their questioning behaviour remained relatively low level in terms of quality. Moreover, three types of peer tutors could be discerned, i.e. questioners, informers and motivational organisers. Finally, although all peer tutors reported diverse organisational, social and didactical concerns and challenges, results showed that different types of tutors struggled with different approach-specific issues and experienced tutoring in a slightly different manner. Taking these issues into account seems crucial for peer tutoring to reach its potential. Implications for peer tutoring programs and training of peer tutors are discussed.