Peer-group mentoring (PGM) is a new model designed to support the professional development of teachers in Finland. This study examines the experiences of mentees participating in PGM and potential differences in the experiences of teachers in general education and vocational education. It also addresses the mentees' perceptions of the results of PGM with regard to the professional, personal and social dimensions of professional development. Quantitative research methods were used. An online survey was completed by 69 teachers in general education and 47 teachers in vocational education (n = 116). The results showed that the participants saw PGM as an important tool for professional development throughout the entire teaching career. In general, there were few significant differences between vocational teachers and their colleagues in general education in their perceptions of PGM. The study further suggests an alternative conceptualisation of professional development based on the following components: development of skills and knowledge, strengthening professional identity and self-confidence, and development of a work community.