Problem behaviours in children with Autism Spectrum Disorder (ASD) are a major source of parenting stress, as they restrict family capacity to maintain quality domestic and social life. It is therefore critical to support parents to manage the problem behaviours of their child with ASD. Recent mindfulness intervention studies have successfully addressed this issue. The current pilot study pursues this line of enquiry and extends the scope of mindfulness intervention by training parents to become a mindfulness teacher of their own child with ASD and problem behaviours, so together they can work on enhancing the quality of their domestic and social life. A total of six dyads of mothers (CA range 34–48 years) and children with ASD and problem behaviours (CA range 8–15 years) participated in a two-stage mindfulness intervention. Mothers attended an 8-week mindfulness program to attain fluency in the theory and practice of mindfulness meditation (Stage 1). Based on this fluency they then taught mindfulness activities to their child (Stage 2). This paper reports on the effects of the mindfulness intervention provided for mothers (Stage 1) and children (Stage 2) as demonstrated by the level of mindfulness, parenting stress, and family quality of life for mothers, and problem behaviours for children. The results highlight overall improvements in the targeted areas. Some benefits, issues, and challenges of mindfulness training for parents and their children with ASD are discussed.