Abstract Objective To compare the neurodevelopmental outcomes of preterm twins at 5½ years by chorionicity of pregnancy. Design Prospective nationwide population‐based EPIPAGE2 (Etude Epidémiologique sur les Petits Âges Gestationnels) cohort study. Setting A total of 546 maternity units in France, between March and December 2011. Population A total of 1126 twins eligible for follow‐up at 5½ years. Methods The association of chorionicity with outcomes was analysed using multivariate regression models. Main outcome measures Survival at 5½ years with or without neurodevelopmental disabilities (comprising cerebral palsy, visual, hearing, cognitive deficiency, behavioural difficulties or developmental coordination disorders) were described and compared by chorionicity. Results Among the 1126 twins eligible for follow‐up at 5½ years, 926 (82.2%) could be evaluated: 228 monochorionic (MC) and 698 dichorionic (DC). Based on chronicity and gestational age of birth, we found no significant differences for severe neonatal morbidity. The rates of moderate/severe neurobehavioral disabilities were similar in infants from DC pregnancies versus infants from MC pregnancies (OR 1.22, 95% CI 0.65–2.28). By gestational age and without twin–twin transfusion syndrome (TTTS), no difference according to chorionicity was found for all neurodevelopmental outcome measures. Conclusions The neurodevelopmental outcomes among preterm twins at 5½ years is similar, irrespective of chorionicity.