Background Early intervention for autism spectrum disorder (ASD) tends to focus on enhancing social communication skills. We report data collected via focus group discussions as part of a feasibility and acceptability pilot randomized controlled trial (RCT) about a new parent group intervention to manage restricted and repetitive behaviours (RRB) in young children with ASD. Methods The focus groups were led by two independent facilitators and followed a semi‐structured topic guide with the aim of considering three key topics: experiences of participating in a RCT, opinions about the intervention and the impact of the intervention on the participants, their children and the family. Results Fourteen participants attended the focus groups. Most participants reported that they had little knowledge of RRB before attending the intervention and that it had had a positive impact on them, their children and their family. Conclusion The findings support the view that there is an unmet need for a parent‐mediated intervention focusing on RRB.