The current study is the first investigation of prenatal methadone exposure on adaptive behaviour in middle-school aged children, and the subsequent relationship with caregiver stress. A cross-sectional design was employed and participants were 27 caregivers of methadone-exposed (ME) children and 26 caregivers of non-exposed (NE) comparison children who completed a Maternal Health Interview and child questionnaires. Results showed that ME children were regarded by their caregivers as having significantly less adaptive behaviour skills overall, as well as poorer scores across the five domains of adaptive behaviour than NE children. Caregivers of ME children reported significantly higher scores on the Sources of Stress scale of general everyday stress than NE caregivers, whilst there were no significant differences between caregivers reports of parenting stress. After controlling for group and socio-economic status (SES) there was no significant relationship between child adaptive behaviour and caregiver general stress. In conclusion, the findings of the current study provide novel information into the research of adaptive behaviour in middle-school aged ME children and their caregivers stress levels. These findings pinpoint the need for the identification of children at-risk in their development of adaptive behaviour skills necessary for the adequate navigation of daily life. These findings also highlight the need for the development of further support systems for caregivers who have identified a lack of social support in their daily lives.