Mothers of hyperactive (M-Hyp) and control children (M-NHyp) estimated the age at which their child and children normally would reach a number of significant developmental milestones. M-Hyp and M-NHyp had similar timetables for normal development while their judgements about their own child's development were different. M-Hyp saw their children as delayed relative to normal development and M-NHyp saw theirs as advanced. This group differences spanned the social, communicative, cognitive and self-care domains. The generality of this effect was particularly surprising as the two groups of children had similar IQ scores. A number of explanations for this are discussed, including the possibility that this finding represents an important generalization of low expectations from the purely social to the communicative/cognitive domains. The implications of this possibility for hyperactive children's development are discussed.