Schools in many countries are beginning to take on extended roles, working with families and communities as well as with students. However, the rationales underpinning such developments are often unclear. This paper reports on case studies of 20 schools developing new roles as part of the national extended services initiative in England. It reports in detail on two of these schools, exploring the rationales for their extended roles elicited in the course of a theory of change- based evaluation. It finds that schools saw no contradiction between their traditional and extended roles because they saw students' academic attainments as shaped by a wide range of personal, family and community factors. It argues that the schools' rationales were coherent, but by no means fully articulated and concludes that dialogue between practitioners, policy makers and researchers is necessary to develop these rationales further.