AbstractIt is well established that children’s school readiness is associated with their later academic achievement, but less is known about whether school readiness is also associated with other measures of school success, such as students’ social and emotional wellbeing. While some previous research has shown a link between early social and emotional development and student wellbeing, results are mixed and the strength of these relationships vary depending on whether data is based on child, teachers or parents ratings and which specific student wellbeing outcomes are measured. The present study explored the association between teacher-rated school readiness (M_age = 5.6 years) across five developmental domains (physical, social, emotional, language and cognitive, and communication and general knowledge) and four aspects of student wellbeing (life satisfaction, optimism, sadness and worries) in Grade 6 (M_age = 11.9 years) in a sample of 3906 Australian children. After adjustment for background child and family-level factors, children’s early physical, social and emotional development were associated with all four wellbeing outcomes in Grade 6, but early language and cognitive skills and communication and general knowledge skills were only associated with internalising behaviours (sadness and worries). Mechanisms through which these different aspects of development might influence later wellbeing are discussed, as well as ways that schools and governments can support students’ social and emotional wellbeing.