Recent experimental evidence suggests that engaging in pretend play can improve children's executive functions (EFs). Yet, evidence regarding how play relates to the development of EF remains sparse. The current study investigated whether preschoolers’ social and solitary pretend play over the course of one preschool year predicted growth in inhibitory control, a key component of EF. Participants were 132 Spanish-speaking preschoolers (Mage = 53 months) from 10 Head Start classrooms in the southwest United States. Multiple 15-s naturalistic observations of children's interactions (e.g., social, solitary) and activities (e.g., pretense, non-pretense) were gathered across free-play classroom contexts. Among observed play behaviors, social pretense was the only predictor of inhibitory control growth in preschool contexts. The current study speaks to the importance of continued research on play-based interventions, especially in diverse populations, and corroborates a growing body of theoretical and empirical evidence for the importance of pretend play in the development of EF. (author abstract)