Mathematics is dominated by an approach to assessment and selection that confl ates challenge and diffi culty with notions of ability and discrimination. In secondary education1, lower attaining students receive a largely remedial (and boring) curriculum, and most students regard themselves as weak mathematically. In this chapter, we explore how ability and assessment serve to produce and create largely negative forms of mathematical identity. We examine the continuities between teachers’ and pupils’ experiences of school mathematics and discuss how teachers’ practices reproduce the same patterns of inclusion and exclusion to which the teachers themselves were subject. Finally, we suggest ways in which assessment could be reconceptualised.