Objective To examine differences in child social competence and parent–child interactions involving children with intellectual disability (ID) or typical development (TD) during a Parent–Child Problem‐Solving Task. Design Mothers and their 9‐year‐old children (n = 122) participated in a problem‐solving task in which they discussed and tried to resolve an issue they disagreed about. The interactions were coded on child and mother problem solving and affect behaviours, as well as the dyad's problem resolution. Results Children with ID (n = 35) were rated lower on expression/negotiation skills and higher on resistance to the task than children with TD (n = 87). Mothers in the ID group (vs. TD group) were more likely to direct the conversation. However, there were no group differences on maternal feeling acknowledgement, engagement, warmth or antagonism. The ID dyads were less likely to come to a resolution and to compromise in doing so than the TD dyads. These group differences were not attributable to differences in children's behaviour problems. Conclusions Children with ID and their mothers had more difficulty resolving problems, and this increased difficulty was not explained by greater behaviour problems. Additionally, with the exception of directiveness, mothers of children with ID displayed similar behaviours and affect towards their children during problem solving as mothers of children with TD. Results suggest that the Parent–Child Problem‐Solving Task is a useful way to assess social skills and associated parental behaviours in middle childhood beyond self‐report. Implications for future research and intervention are discussed.