This article investigated the occurrence and impact of sleep problems during the early school years. Data from the Longitudinal Study of Australian Children was analysed, for children aged 4 to 5 years at wave 1 and then 6 to 7 years at wave 2. The timing and severity of sleep problems was compared to parent- and teacher-reported outcomes including quality of life, language skills, behaviour, and learning. The study found that sleep problems during the school transition tears are common and are associated with poorer child outcomes.