Background: Sleep is an important physiological need for children with intellectual disabilities and their mothers. The present study aims to obtain detailed information on the factors that are hindering and facilitating the sleep quality of children with intellectual disabilities and their mothers. Method: Twenty-one mothers of children with intellectual disabilities aged 2-18 years were interviewed to identify their perceptions of the factors that hindered or facilitated the quality of their sleep and that of their children. The interviews were transcribed, coded and analysed thematically using the MAXQDA qualitative data analysis program. Findings: The interview data generated three main themes relating to factors that are hindering and facilitating sleep quality in children with intellectual disabilities and their mothers: physiological, psychological and environmental factors. Conclusion: Mothers reported that sleep problems negatively affect themselves and their children with intellectual disabilities. Parent education and counselling on topics of environmental regulation, methods of coping with stress and establishing and maintaining routines are recommended to enhance sleep quality.