Background: Children with intellectual disabilities have high rates of behaviour problems. This study explored parents' causal beliefs and attributions for general problematic child behaviour in children with different aetiologies of intellectual disabilities. Materials and Methods: Ten parents of children with intellectual disabilities participated in interviews about their child's problematic behaviour. Results: Thematic analysis using NVivo revealed that parents viewed their child's problematic behaviour not only as caused by the child's intellectual disabilities but also by other causes unrelated to the intellectual disabilities, as well as by aspects of the social environmental context. Some causes were viewed as stable and uncontrollable and others as unstable and controllable. In addition, parents showed a strong sense of responsibility for child behaviour. Conclusions: Parents of children with intellectual disabilities do not solely interpret their child's problematic behaviour through the intellectual disabilities but incorporate the environment and causes and attributions that are not related to the intellectual disabilities, which may help to promote more effective parenting.