This paper arises out of an initial exploratory study of teachers’ professional identity as an important factor in education reform and school improvement. It builds on previous work such as the ‘Future of the Teaching Profession’ survey commissioned by Education International using research tools designed in that project to explore how teachers construct their professional identities in the context of their particular institutional circumstances – their schools. Data are collected within the context of a Teaching Schools Alliance which is a particular form of school clustering aimed at sharing practice and promoting teachers’ professional development. The focus on identity here seeks to move the analysis beyond the limitations of concepts such as the behaviourist ‘staff training’ and the more sophisticated ‘continuing professional development’. The hypothesis explored here is that educational change and improvement requires that we pay attention to the more fundamental question of how teachers see themselves as professionals. The paper also analyses the organisational conditions which support and sustain the growth of particular forms of professionality.