Abstract Objective To measure the prevalence and social impacts of sleep problems in Australia. Design Cross-sectional national adult online survey. Setting Community-based sample. Participants Australian adults ≥18 years, n = 1011. Results Self-reported inadequate sleep, of either duration or quality, and its daytime consequences affect 33%-45% of adults. Diagnosed sleep apnea is reported by 8%, significant insomnia by 20%, and restless legs by18% of adults. Besides specific clinical sleep disorders, poor sleep habits were common. Average reported sleep time is 7 hours, although 12% sleep less than 5½ hours and 8% over 9 hours. Three-quarters (76%) of those who sleep less than 5½ hours report frequent daytime impairment or sleep-related symptoms. Frequent, loud snoring is reported by 24% of men and 17% of women. Among these, 70% report daytime impairment or other sleep-related symptoms. Twenty-six percent report Internet use most or every night just before bed and frequent sleep difficulties or daytime impairments. Similarly, 16% of working adults do work just before bed and also have frequent sleep difficulties or daytime sleep-related symptoms. Younger adults (18-34 years) sleep around 1 hour longer before non-work days than working days compared with 18 minutes in older age groups. In the past 3 months, 29% of adults report making errors at work due to sleepiness or sleep problems. Driving while drowsy at least every month is reported by 29% of people, 20% have nodded off while driving, and 5% have had an accident in the past year because they dozed off. Conclusion Sleep problems and daytime consequences are endemic among Australian adults. A focus on healthy sleep at a policy level as well as increased clinician and public awareness may be warranted.