Maternal nutritional factors during pregnancy have been linked to foetal brain development and subsequent offspring behaviour. Less is known about associations between maternal dietary patterns and offspring behaviour.Within a population-based cohort, we assessed maternal diet using a food frequency questionnaire. Three dietary patterns were derived by means of Principal Component Analysis. Child internalising (emotionally reactive, anxious/depressed or withdrawn, having somatic complaints) and externalising problems (inattention, aggression) were assessed with the Child Behaviour Checklist at 1.5, 3 and 6 years in 3104 children. We assessed the association of maternal Mediterranean, Traditionally Dutch and Confectionary dietary pattern during pregnancy with child internalising and externalising problems.After adjustment, the Mediterranean diet was negatively associated (ORper SD in Mediterranean score = 0.90, 95% CI: 0.83-0.97) and the Traditionally Dutch diet was positively associated with child externalising problems (ORper SD in Traditionally Dutch score = 1.11, 95% CI: 1.03-1.21). Neither diet was associated with internalising problems.Both low adherence to the Mediterranean diet and high adherence to the Traditionally Dutch diet during pregnancy are associated with an increased risk of child externalising problems. Further research is needed to unravel the effects of nutrient interplay during and after pregnancy on child behavioural development.