The retention of teachers is one of the key challenges currently facing schools today. The imperative to bring more teachers into the profession and keep them there has never been more urgent. With Government interventions in England mainly concentrated on the recruitment of teachers into the state sector, little consideration has been given to the scale of teachers leaving or their reasons for doing so. National data masks significant local variations and the overall extent of the attrition problem. Impact from the Retention and Recruitment strategy as a strategic Government driver has yet to be determined. The teacher supply crisis cannot be solved by recruitment drives alone. Reducing teacher attrition could well be the key lever to overcoming the acute recruitment shortage now faced in England. By examining a number of school-related factors, this paper argues that reducing attrition is vital for the sustainability of the teacher workforce, pupil performance and school improvement and the paper concludes by making recommendations for policy makers.