Thesis advisor: Marina Vasilyeva / Children's early math development is essential for their later academic achievement (Duncan et al., 2007). Yet, research shows that children from lower socioeconomic (SES) backgrounds encounter disadvantages even before starting school. This dissertation includes three empirical studies conducted in China, aiming to enhance our understanding of SES-related disparities in the home math environment and to develop cost-effective interventions for families in need. Study One suggests that parents of preschool children from high SES background demonstrate higher math efficacy, lower math anxiety, and higher math skills than those with higher levels of education. Moreover, high-SES parents engage more often in informal math activities with their preschool children and provide more enriched math talk. Path analysis further reveals an indirect path from SES to children’s math skills via parents’ characteristics and home math environment. Building on Study One, Study Two demonstrates that higher-educated parents have a greater tendency to spontaneously focus on numerical aspects in their environment, a tendency that significantly correlates with both the quantity and quality of their math talk. Study Three suggests that parental math talk can be implicitly increased by manipulating play contexts and toy features. Math-relevant contexts, like pretend grocery shopping, might elicit more math talk. Furthermore, material features within these contexts may shape the nature and amount of math talk: homogeneity increases discussions about absolute magnitude, while boundedness increases talk about relative magnitude.Theoretically, this dissertation enriches our understanding of the mechanisms underlying SES disparities in early math development. Practically, it identifies potential directions for designing cost-effective interventions to enhance home math environment. / Thesis (PhD) — Boston College, 2024. / Submitted to: Boston College. Lynch School of Education. / Discipline: Counseling, Developmental and Educational Psychology.