Research shows that there is a need to develop psychosocial interventions specifically for young people with intellectual or developmental disabilities (IDD) and their families to optimize their mental health. In the present pilot study, an 8-week mindfulness-based group was conducted with eight adolescents with IDD and their parents. Qualitative evidence suggests that there may be some benefits to joint groups for youth and parents. Both parents and youth enjoyed the group and gained insight into themselves and each other. A trend was observed where youth participants' self-reported mood improved following each session and their social behaviours were reported by parents to improve as well. Some challenges were encountered, however. Despite parents' involvement in the group, some participants were reported to be resistant in practicing mindfulness skills outside of sessions. This study expands on the therapeutic modalities available for youth with IDD and their families, showing that 90 min mindfulness-based intervention may help youth with IDD learn how to manage their emotions from within.