Based on a sample of 89 aggressive clinic-referred children, aged between 9 and 11 years, a longitudinal study of 1-year duration was conducted to examine (a) whether the children's perception of control and support of their mothers’ to them predicted their hostile attribution of intent and hostile response selection, and (b) whether these hostile biased social cognitions mediated the relationships between their perceived maternal behaviours and their aggression. Participants completed a questionnaire covering both the perceived maternal control and support. One year later, their hostile attribution of intent and response selection, and aggression, were measured. Results showed that perceived maternal control and perceived maternal support were associated positively and negatively, respectively, with both the social cognition measures. Also, the social cognition measures mediated the relationships of the perceived maternal measures with aggression. The findings are discussed in terms of how children's hostile biased relational schemas and scripts, developed from negative parenting and insecure attachment, favour more hostile social cognitions, and how these in turn mediate children's current hostile biased social behaviours.