Psychologists have long been interested in understanding how the early social environment impacts children’s behavior, thoughts, and minds. From birth, children are embedded in a world rich with social relationships; however, there have been very few tools with which one could even begin to quantify the depth and breadth of children’s early social relationships. In this dissertation, I harness the insights and power of social network analysis to demonstrate that developmental psychologists can use social networks to capture and describe early social environments. Once early social experience is conceptualized as network properties, social network theory can be used as a framework to generate questions about how early social environments relate to social cognitive development. In Chapter 1, I describe the method I created – The Child Social Network Questionnaire. Using descriptive social network data from over 300 American children, I demonstrate that network properties can be used to provide a quantitative analysis of children’s early social experience and how that experience varies across development, social group membership, and childcare experiences. In Chapter 2, I test the hypotheses generated from social network theory about how network properties – Network Size and Network Language Diversity – relate to 3-year-old’s perspective-taking (PT) ability. Results show Network Size is positively related to children’s PT skill and exploratory analyses suggest that Network Language Diversity has different effects on social cognitive skill in different sized social networks. In Chapter 3, I use preschooler’s network properties to explore how Network Racial Diversity relates to children’s racial friendship choices. Across several analyses, I find racial outgroup exposure is not created equal; how it relates to racial preferences depends on the Network Size, Network Structure, and broader social environment.