The purpose of our study was to examine the ways in which parents engage in play with their children within the family context and to establish which parental play behaviour predicts the play behaviour of their children during interactive play with toys. The sample included 58 children from 2;6 to 6 years old and their parents. The parent-child dyads were videotaped in the home setting during a 30-minute interactive play period with both structured and unstructured toys, chosen by the researchers. The interactive play was analysed using the "Scale for Observing Child-Adult Play" [Marjanovic-Umek, L., & Fekonja-Peklaj, U. (2012). "Lestvica za opazovanje otroka in starša med igro" [Scale for Observing Child-Adult Play]. Ljubljana: Oddelek za psihologijo, Filozofska fakulteta], which consists of five categories for assessing the adult's play and four categories for assessing the child's play. The results obtained showed positive correlations between parents' and children's play behaviour. The regression analysis showed that the parental use of mental transformations was the strongest predictor of a child's play behaviour; namely, the development of the play content and play frame as well as the child's use of mental transformations. The findings provide important possible implications, especially in the sense of scaffolding children's symbolic play.