The current study sought to determine whether hypertensive diseases of pregnancy (gestational hypertension and pre-eclampsia) are associated with neurocognitive outcomes in middle childhood. Participants were members of the Western Australian Pregnancy Cohort (Raine) Study. Data were available for 1389 children (675 females; mean age = 10.59 years; SD = 0.19). Twenty-five per cent of these participants were offspring of pregnancies complicated by either gestational hypertension (n = 279), or pre-eclampsia (n = 34). Verbal ability at age 10 years was assessed with the Peabody Picture Vocabulary Test – Revised (PPVT-R), and non-verbal ability with Ravens Colored Progressive Matrices (RCPM). Separate multivariable regression analyses, incorporating sociodemographic, antenatal, obstetric and postnatal covariates, investigated the effect of a two- (normotensive pregnancy vs. hypertensive pregnancy) and three-level (normotensive pregnancy vs. gestational hypertension vs. pre-eclampsia) predictor variable on PPVT-R and RCPM scores. Offspring of pregnancies complicated by maternal hypertension (gestational hypertension or pre-eclampsia) had a mean PPVT-R score that was 1.83 ([95% confidence interval (CI) −3.48, −0.17], P = 0.03) points lower than children from normotensive pregnancies. Multivariable regression analysis also identified a significant inverse association between the three-level predictor variable and offspring PPVT-R scores (P = 0.02). Gestational hypertension (without pre-eclampsia) reduced offspring PPVT-R scores by 1.71 points [95% CI −3.39, −0.03] and pre-eclampsia led to a reduction of 3.53 points [95% CI −8.41, 1.35], although this latter association did not achieve statistical significance. There was no effect of the two- (P = 0.99) or three-level (P = 0.92) predictor variable on RCPM scores. Maternal hypertensive diseases of pregnancy are a risk factor for a small reduction in offspring verbal ability.