BACKGROUND: Sleep problems are common in children with an intellectual disability (ID), often lasting for many years. Many parents do not perceive their child to have a sleep problem, do not believe treatment is possible and do not seek treatment. This paper examined prevalence and duration of sleep problems in children with an ID and considered parental perceptions of sleep problems and views towards treatment. METHOD: The paper reports on two studies (n = 149 and 243 respectively) of children between 3 and 18 years, with a range of disabilities. Parents in each study completed a questionnaire about their child's sleep problems, and the type and effectiveness of any treatment used to address their child's sleep problems. RESULTS: Prevalence rates ranged between 25.5% and 36.2% for sleep problems with an average duration of between 6 and 9 years. Around half of parents had sought treatment for their child's sleep problem in Study 1, while 76% had done so in Study 2. Parental ratings regarding treatment effectiveness were higher in Study 1 than in Study 2. Contrary to expectations, behavioural treatment was not rated as significantly more effective than other treatments in either study. CONCLUSIONS: While sleep problems are common and chronic in children with an ID, parents may not recognize a sleep problem as present, often do not seek treatment for their child's sleep problems, and treatment advice and effectiveness is very variable. Thus, further research and parent and professional education regarding the identification and treatment of sleep problems in these children is required.