To explore patterns in parent-reported child sleep health and to investigate connections between such patterns and school readiness for newly enrolled prekindergarten (PreK) attendees from racially and ethnically diverse, low-income backgrounds. Study design: In a secondary analysis from a larger multiple-cohort longitudinal observational study of prekindergartners in low-income families, parental reports of sleep health for 351 children (mean age, 52.8 +-3.5 months) during the first month of PreK were analyzed. Children also had completed direct assessments measuring language, literacy, mathematics, and executive functioning, and teachers rated children’s social–emotional–behavioral competencies and approaches to learning at PreK entry. We performed latent class analyses to identify patterns in sleep health and used regression models to examine concurrent associations between child sleep health patterns and school readiness competencies across 6 domains: language, literacy, mathematics, executive functioning, social–emotional–behavioral, and approaches to learning. (author abstract)