This analysis examines the relationship between participating in the Supplemental Nutrition Assistance Program (SNAP) and school readiness skills, specifically in early reading, early math, and approaches to learning skills, among low-income children in their preschool to kindergarten-entry years. We also investigate whether this relationship differs depending on depth of household poverty. By using wave 3 and kindergarten-entry wave from the Early Childhood Longitudinal Study Birth Cohort (ECLS-B) data and the child fixed-effects approach as its main empirical strategy, we find strong evidence that SNAP is positively related to children's early math skills (0.22 standard deviation increase) and that this relationship is stronger for children who were in deep poverty and/or poverty prior to their receipt of SNAP. For early reading skills, although we find no significant main effect, the relationship between SNAP and early reading is stronger for children who lived in deep poverty before their SNAP receipt, compared to children who were not as poor. We also find suggestive evidence that SNAP is related to approaches to learning skills (0.3 standard deviation increase), though marginally significant, and that the relationship is much stronger among children who were in deep poverty than those who were not. Through these results, we provide strong support for the role of SNAP, especially for the most economically disadvantaged families, in advancing key school readiness skills that are important to children's developmental outcomes. (author abstract)