Children with intellectual disability receiving residential support, according to the Swedish Disability Act, need substantial support to cope with everyday life. These children have cognitive and communicative limitations, entailing difficulties for staff in consulting the children regarding their support arrangements. In addition, due to lack of research there are knowledge gaps and uncertainties concerning how staff can provide the children’s support. To deliver high qualitative support, research suggests that disability organisations should (1) continuously work with quality improvement, (2) adopt a multi-dimensional framework that explains human functioning and disability as a basis for understanding individual support needs, and (3) use person-centred approaches. Based on these principles, this study has applied a realist evaluation to identify enablers and barriers during the implementation of an improvement programme aimed at improving staff’s ability to provide support to children living in special residences.