This study examined the developmental trend of pretend play behaviour and the effect of partner's gender in Singaporean preschoolers. Peer dyadic play among 70 children, ranging in age from three to five years, was observed in a standardised toy play context. Videotaped recordings of the play were analysed using two scales--the Smilansky Scale for Evaluation of Dramatic and Socio-dramatic Play and the Symbolic Play Scale. The results indicated an age-related developmental trend for pretend play in general; no main effect for gender and gender composition of dyads was found. However, remarkably significant gender composition effects were identified in certain age groups, with children from same-gender dyads outperforming those from mixed-gender dyads. The period between ages three and four was identified as critical for pretend play development, and the fifth year of life was identified as critical for the development of gender segregation in play behaviours.