Thirty-three children with Down syndrome (DS), whose developmental ages (DA) ranged from 17 to 44 months, and 39 normally developing (ND) children, whose DA levels were approximately equivalent, were observed in two play conditions. In the first condition, children played independently while their mothers completed a questionnaire. Next, mothers were instructed to play with their child. Multivariate analyses yielded few significant differences between DS and ND groups for the nonsocial play condition. However, children with DS had lower levels of sustained engagement, and their mothers were more frequently intrusive during social play. Correlational analyses revealed that play quality and sustained engagement with toys were significantly related for the nonsocial play segment, but only for the ND group. Sustained engagement with toys during nonsocial play significantly predicted play quality during social play for both DS and ND samples. During social play, maternal variables were associated significantly with both play quality and sustained engagement with toys for the DS group, but not for ND children. The results suggest that DS and ND children follow parallel trajectories of development with respect to play quality and sustained engagement with toys. However, the social scaffolds supporting these trajectories may differ. Mothers of children with DS tend to focus on and manipulate their child's attention to toys more directly than do mothers of ND children.