OSA can occur at any age, and is more common if a person is overweight, sleeps on their back, uses alcohol or sleeping tablets prior to going to sleep, or has nasal obstruction or a narrow upper airway (e.g. enlarged tonsils or differences in face or jaw shape).

In New Zealand, OSA is estimated to affect 3−5% of children and is one of the most common respiratory disorders of childhood. A minimum of 4% of adult males and 2% of adult females experience OSA, though most cases are undiagnosed.
OSA rates are higher among Māori and Pacific people: OSA is twice as common in Māori males compared to non-Māori males, Māori and Pacific people tend to have more severe OSA and more co-morbidities, and there are ethnic disparities in the ongoing use of CPAP.