This article discusses teachers' moral learning in professional learning groups and corresponding challenges for teachers' moral professionalism. A professional learning programme aimed as understanding the moral dimension of teaching was conducted. A framework for moral learning was developed based on a review of the literature of teacher professional learning. Teachers' moral learning itself focuses on extending and deepening the understanding of one's own frame of reference, which influences teachers' moral sense-making of their daily teaching practice. The study examined the changes caused by the moral learning process by conducting seven focus-group interviews. Findings indicate that through participation in the professional learning programme, teachers are more aware of their frames of reference which were mainly implicit before the programme. Results show teachers have (1) an increased self-awareness of one's own frame of reference and (2) they are more open for other viewpoints, and (3) are also more inclined/capable of taking into account the meaning of their own frame of reference and its influence on pupils. Finally, we identified features that teachers considered as being important to strengthening their moral professionalism.