Using a longitudinal adoption design, we aimed to (a) capture the heterogeneity of children’s peer play behavior, and (b) examine genetic and parenting factors that contribute to profiles of peer play behavior. The sample consisted of 178 children age 4.5 years. Preschool teachers reported on children’s play behavior. Four distinct profiles of peer play behaviors were identified: socially competent children who were well connected with peers (the socially connected profile: SC), children who were slightly disruptive yet socially interactive (the connected-slightly disruptive profile: CD), children who were shy and socially marginalized (the withdrawn profile: WD), and children who were highly disruptive and socially disconnected (the disconnected-disruptive profile: DD). Children in the DD profile had adoptive mothers who were more overreactive than did those in the SC profile. Children in the WD profile had adoptive fathers who were more overreactive than did the SC profile children. Compared with the CD children, the DD profile children received less positive reinforcement from adoptive mothers. Children in the DD profile had birth mothers with lower sociability than did the SC children (i.e., SC and CD profiles). The results suggest that different profiles of play behaviors in preschool children may have distinct clusters of environmental and genetic correlates