ObjectiveTo examine the association between gestational age at birth across the entire gestational age spectrum and special educational needs (SENs) in UK children at 11 years of age.MethodsThe Millennium Cohort Study is a nationally representative longitudinal sample of children born in the UK during 2000–2002. Information about the child’s birth, health and sociodemographic factors was collected when children were 9 months old. Information about presence and reasons for SEN was collected from parents at age 11. Adjusted relative risks (aRRs) were estimated using modified Poisson regression, accounting for confounders.ResultsThe sample included 12 081 children with data at both time points. The overall prevalence of SEN was 11.2%, and it was inversely associated with gestational age. Among children born <32 weeks of gestation, the prevalence of SEN was 27.4%, three times higher than among those born at 40 weeks (aRR=2.89; 95% CI 2.02 to 4.13). Children born early term (37–38 weeks) were also at increased risk for SEN (aRR=1.33; 95% CI 1.11 to 1.59); this was the same when the analysis was restricted to births after labour with spontaneous onset. Birth before full term was more strongly associated with having a formal statement of SEN or SEN for multiple reasons.ConclusionChildren born at earlier gestational ages are more likely to experience SEN, have more complex SEN and require support in multiple facets of learning. This association was observed even among children born early-term and when labour began spontaneously.