Aim To assess the risk of a wide spectrum of neurodevelopmental disorders (NDDs) in offspring of mothers with type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), and gestational diabetes mellitus (GDM). Method This retrospective cohort study included 877 233 singletons born between 2004 and 2008 in Taiwan. Children were followed up to 2015 for diagnoses of NDDs, including autism spectrum disorder (ASD), attention‐deficit/hyperactivity disorder (ADHD), developmental delay, intellectual disability, cerebral palsy, and epilepsy/infantile spasms using health insurance claims data. We performed Cox regression models to estimate the relative risks of NDDs associated with maternal diabetes. Covariates included parental age, year of birth, child sex, family income, urbanization level, hypertensive disorder, and preterm delivery status. Results In utero there were 338 (0.04%) children exposed to T1DM, 8749 (1.00%) to T2DM, and 90 200 (10.28%) to GDM. The effect of T1DM on NDDs was the largest, followed by T2DM, then GDM. T1DM was associated with an increased risk of developmental delay, intellectual disability, and epilepsy/intellectual spasms in offspring. T2DM was associated with an increased risk of ASD, ADHD, developmental delay, intellectual disability, cerebral palsy, and epilepsy/intellectual spasms. GDM was associated with an increased risk of ASD, ADHD, and developmental delay. Interpretation Maternal diabetes during pregnancy, including T1DM, T2DM, and GDM, is associated with an increased risk of some NDDs in offspring. Kaplan–Meier cumulative incidence of developing neurodevelopmental disorders in children born to mothers without diabetes or mothers with type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), or gestational diabetes mellitus (GDM). This original article is commented on by Sheiner on pages 863–864 of this issue.