Sleep-disordered breathing in children includes disorders of breathing that affect airway patency e.g. obstructive sleep apnoea (OSA), and also conditions that affect respiratory drive (central sleep disorders) or cause hypoventilation, either as a direct central effect or due to peripheral muscle weakness. OSA is an increasingly-recognised clinical entity affecting up to 5.7% young children. OSA, if left untreated, may be associated with adverse effects on growth and development including adverse cognitive and behavioural outcomes. Evidence also exists to suggest that untreated OSA may impact on later cardiovascular risk. Close attention should be paid to assessing and investigating this relatively common condition. This review deals with the presentation, investigation, management, and sequelae of OSA, as well as providing an overview of the presentation, investigation, management of central apnoea in children.