Research Findings: School readiness is highly salient in South Africa (SA), a country with extreme and persistent inequities that undermine early childhood development. The aim of this short-term longitudinal study was to identify social ecological factors associated with school readiness in young children from low-income settings in Cape Town, SA. Participants were 152 3–5-year-old children (55percent female, not attending early childhood care and education (ECCE) settings at recruitment) and their primary adult caregiver from low-income settings. Linear regressions found that, compared to home- and community-level factors, child-level factors were the strongest predictors of scores on the International Development and Early Learning Assessment (IDELA, total and subscale scores for literacy, numeracy, social emotional, and motor). At the child level, attending ECCE services was the strongest predictor, followed by early numeracy and age. Household socioeconomic status positively predicted social emotional scores; dysfunction in the parent–child relationship negatively predicted literacy and total school readiness scores. Practice or Policy: These findings contribute to a contextually relevant understanding of school readiness in low-income SA settings. Greater understanding can lead to more effective mitigation of risks and amplification of protective factors within policy and practice so that early childhood development can be optimized in these settings.