Children with intellectual disability are at increased risk of experiencing poor health relative to their typically developing peers. Previous research indicates that exposure to socio-economic disadvantage contributes towards this disparity but that additional factors (including parenting practices) may be involved in mediating/moderating pathways. This study examined duration of breastfeeding amongst children with and without intellectual disability by a secondary analysis of data from the UK Millennium Cohort Study. Children with intellectual disability were significantly less likely to have been ever breastfed; breastfed exclusively or at all at 3 months or breastfed at all at 6 months relative to children without intellectual disability. None of these differences remained significant when other psycho-social risk factors for reduced breastfeeding were controlled for. The study adds to both the sparse literature on breastfeeding practices amongst families of children with intellectual disability and research demonstrating relationships between socio-economic disadvantage and wellbeing for children with intellectual disability.