Being school-ready when transitioning to the primary school system has been associated with favourable outcomes during schooling and adult life. While children living in socio-economically disadvantaged areas may be at a higher risk of being less school-ready, research in the area has highlighted that not all children experience such a delay. This study examined a range of factors that may account for differences in outcomes across five school readiness domains (physical health and well-being, social competence, emotional maturity, language and cognitive development, and communications skills and general knowledge) within a sample of children living in socio-economically disadvantaged areas. Drawing on data from a sample of five-year-old children involved in the Preparing for Life (PFL) evaluation in Ireland, this study explored the role of child and early environmental factors in facilitating or hindering children's development across these school readiness domains. Statistical analysis identified child's sex, parental involvement and learning materials at home, parent-child interactions, mother's attempt to breastfeed, and mother-child attachment as significant predictors of school readiness after accounting for other factors. Findings contribute to the Irish and international literature on the role of early demographical and environmental factors in shaping school readiness, especially for children from socio-economically disadvantaged areas.