<p>Despite its developmental importance, young children’s object-oriented play often remains undervalued in educational practice. This observational study investigated how object-oriented play develops during early childhood and examined its underlying behavioral trajectory. We observed 128 children (ages 2–4, 50% female) on two occasions, using a cohort-sequential design. During each session, children played with a fixed set of objects. Their actions were systematically coded and analyzed through a combination of qualitative methods and mixed model regression analyses. Results show that as children grow older, their object-oriented play becomes increasingly complex, characterized by a higher number of distinct actions, involvement of more objects, and increased repetition. While sensorimotor exploration tends to decrease with age, physical manipulation increases. Notably, these two forms of behaviors often co-occur, suggesting they are not separate behavioral phenomena but intertwined components of a broader developmental process. Instances of mental manipulation, though more difficult to observe reliably, became more apparent around age three. These findings offer valuable insights into the relation between object-oriented play and young children’s development and highlight its relevance for early childhood education and care.</p>