Mindfulness-based therapies are rising in popularity. However, evidence for their effectiveness in reducing psychological distress and enhancing wellbeing for families living with autism spectrum disorder (ASD) is limited. A systematic search identified 10 independent studies, involving a pooled sample of 233 children and adults with ASD and 241 caregivers. Hedges' g effect sizes with associated 95% confidence intervals, in addition to heterogeneity, were calculated using a random-effects model. Caregivers, children and adults who received mindfulness all reported significant gains in subjective wellbeing immediately post-intervention. Available data indicated intervention effects were maintained at 3-month follow-up. Mindfulness presents a promising intervention strategy in ASD populations, however more controlled research is required to determine its precise efficacy for affected families and subgroups.