This paper offers an overview of what motivates and challenges Australian supervising teachers to work with preservice teachers in their classrooms. In the contemporary Australian context of new National Professional Standards for Teachers, a new national curriculum and new standards for Initial Teacher Education programs, what motivates and challenges supervising teachers becomes a focus for professional learning through analysis presented in this paper. Data are reported from a national data set that includes 314 responding supervising teachers who took the "Mentoring Perspectives Inventory" from 2012-2014. The MPI data are aggregated in this paper to suggest that the wider system of teacher education could benefit from attention at various levels of interest to develop the underlying knowledge base of supervising teachers and our understanding of how they are challenged and motivated in their work with preservice teachers.