This text examines the key role that the teaching profession has to play in school effectiveness and improvement. It argues that, for this role to be best realized, effectiveness and improvement efforts need to be distanced from a mechanistic performance management approach; their relevance to practice needs to be made more explicit; and the importance of individual and institutional flexibility and on-going learning in coping with a system marked by unpredictability must be recognized. Crucial to this is the need for teachers themselves to become more directly involved in the identification, exploration and analysis of factors and issues in their workplace in order that they may become contributors to effectiveness and improvement work rather than simply interpreters and recipients of it.