The exploration and/or manipulation of objects and materials, referred to as object-oriented play (OOP), is one of the most prominent activities children engage in during early childhood. Especially within early childhood education, it is important to be able to assess and understand OOP, its developmental trajectory, and developmental value. This can support early childhood educators to successfully guide or enrich children's OOP, so it becomes a context in which learning can take place. During the past decades, three dominant theoretical perspectives have explained and assessed certain (developmental) aspects of OOP: (1) genetic epistemology, (2) cultural historical psychology, and (3) evolutionary psychology. After reviewing the literature concerning OOP according to each theoretical perspective, this paper aims to synthesize these existing theories into a unified theoretical framework. This theoretical framework can be a starting point for future research on OOP in early childhood (education). We answer the following research questions: Q1. What are the defining labels and features of the exploration and/or manipulation of objects and materials by children in early childhood?; Q2. What is the developmental trajectory of the exploration and/or manipulation of objects and materials by children in early childhood?; Q3. What is the developmental value of the exploration and/or manipulation of objects and materials by children in early childhood?