Children with an intellectual disability (ID) are at high risk of developing sleep problems. The extent to which the prevalence and nature of sleep problems in these children is dependent on the disorder underlying their intellectual impairments remains unclear. This study examined and compared parental descriptions of sleep problems in children with autism (n = 37), Down syndrome (DS; n = 15), Prader-Willi syndrome (PWS; n = 29), presumed familial intellectual disability (FID; n = 29), and typically developing children (TD; n = 55) in order to determine any influences of disorder on sleep patterns. The prevalence of sleep problems in the disability groups was at least four times higher than for TD children. Sleep problems were more prevalent in autism than the other disorders. Settling difficulties and co-sleeping were more common in the children with autism, whereas sleep maintenance problems were common in autism, DS, and FID, and daytime napping and excessive daytime sleepiness differentiated the children with PWS. These findings are discussed in light of the specific disorders, and with respect to the impact that sleep problems can have on the child and his/her family.