The interaction between people with intellectual disabilities and professional carers is often influenced by communicative difficulties contributing challenging behaviours. The aims of this study were to evaluate to a web-based training program aimed at improving carers' abilities to interact with people with learning disabilities who exhibit challenging behaviours and to explore carers' experiences of participating in such a program. A single-subject experimental design and mixed methods were used to integrate qualitative and quantitative data. Triangulation of questionnaires, interviews with carers, and assessments of one woman's behaviour was performed. The participants were professional carers aged 20 to 55 years. The web-based training program increased carers' abilities to handle challenging behaviours and decreased challenging behaviours in daily care. The program improved the opportunities to offer training to carers who work in community-based accommodations with limited time to receive training.