Teachers learn to be teachers. The process is most intense and explicit in the early years of teaching but continues throughout a teacher's career. Educational reform programmes, school strategies for staff development and individual plans for professional development are based upon views about the conditions which optimise teachers' learning, whether implicit or explicit. Policymakers, teacher educators, senior managers in schools and teachers themselves will be more effective with a fuller understanding of those conditions. The paper outlines two complementary accounts that analyse the conditions: Peter Ashworth's work on adult learning as participatory hermeneutics and the authors' work on active professional location. These are used as a basis for examining the conditions for teachers' learning provided in educational reforms at national level, through professional associations and in schools. Having clarified some principles for professional learning we propose some practical implications for teachers and those concerned with their continuing development.