In England and Wales government pressures to raise attainment has led many schools to implement structured “ability” grouping in the form of setting. The introduction of selective grouping has been justified with the assumption that the differentiation of students by “ability” advances students’ motivation, social skills, independence and academic success in national tests and examinations because students are “better engaged in their own learning”. This paper critically engages with this assumption. Drawing upon qualitative research conducted in primary and secondary mathematics, science and English setted classrooms in England the aim of this literature review is to consider how teachers’ pedagogic practices with low, middle and high “ability” sets facilitates and/or constrains students’ learning and potential achievement. We also explore why, despite strenuous criticism and moves towards egalitarianism in schools, the segregation of students on the basis of “ability” continues to be a common feature in schools in England and Wales. This literature review draws attention to a number of substantive issues including (but not restricted to) fixed and permanent grouping; the potential misplacement of students to sets and a culture of stereotyping where learners within a set are taught as a single homogenous unit. We conclude the paper by suggesting foci for future research in the hope of eliciting renewed critical interest in and investigation of setting by “ability” in a broader range of subjects of the curriculum.