Background: Parenting behaviours influence many domains of child development, and recent work has demonstrated the specific effects of parenting on the development of executive function (EF) abilities. The relationship between parent-child interaction patterns and EF has been examined in typically developing (TD) children but has not yet been examined in dyads where the child has a diagnosis of Down syndrome (DS). Method: The current study examines the differences in patterns of parenting behaviours between DS dyads and dyads with TD children equated on nonverbal mental age. DS dyads (n = 42), child ages 59 to 118 months, and TD dyads (n = 28), child ages 30 to 49 months, participated in a modified version of the Parent-Child Challenge Task. Parent directive and teaching behaviours were coded, along with child compliance and noncompliance. Child participants also completed a laboratory measure of inhibition and working memory, and parents completed the Behaviour Rating Inventory of Executive Function-Preschool. Results: There was a greater frequency of parenting directives and child compliance in the DS dyads, and parents of children with DS were more likely to follow child compliance with directives than parents of TD children. In both groups, parenting directive behaviour was a significant predictor of child EF laboratory performance. Conclusions: Results characterise the relationship between specific parenting behaviours and child EF in DS and TD dyads. The implications for parent training and intervention are discussed.