Children with special educational needs (SEN) are known to experience lower average educational attainment than other children during their school years. But we have less insight into how far their poorer educational outcomes stem from their original starting points or from failure to progress during school. The extent to which early identification with SEN delivers support that enables children who are struggling academically to make appropriate progress is subject to debate. This is complicated by the fact that children with SEN are more likely to be growing up in disadvantaged families and face greater levels of behavioural and peer problems, factors which themselves impact attainment and progress through school. In this paper, we evaluate the academic progress of children with SEN in England, drawing on a large-scale nationally representative longitudinal UK study, the Millennium Cohort Study, linked to administrative records of pupil attainment. Controlling for key child, family and environmental factors, and using the SEN categories employed at the time of data collection, we first establish that children identified with SEN in 2008, when they were age 7, had been assessed with lower academic competence when they started school. We evaluate their progress between ages 5-7 and 7-11. We found that children identified with SEN at age 7 tended to be those who had made less progress between ages 5 and 7 than their comparable peers. However, children with SEN continued to make less progress than their similarly able peers between ages 7 and 11. Implications are discussed.