Background: Parental mentalising difficulties are robustly linked to caregiving problems. Mothers with intellectual disability are at risk for caregiving problems, but knowledge on their parental mentalising abilities is lacking. The present study aimed to fill this gap. Method: Thirty mothers with mild intellectual disability, and 61 comparison mothers with ADHD, were assessed for parental mentalising using the Parental Reflective Functioning Questionnaire. Contributions of intellectual disability, maternal exposure to childhood abuse/neglect and psychosocial risk to parental mentalising were examined through hierarchical regression analysis. Results: Mothers with intellectual disability had a heightened risk for parental mentalising difficulties, in the form of elevated prementalising. Intellectual disability and cumulative childhood abuse/neglect uniquely predicted prementalising among the mothers, whereas cumulative psychosocial risk added to the risk for prementalising specifically among mothers with intellectual disability. Conclusions: Our findings support contextual models of caregiving, and suggest a need for mentalisation-based support for parents with mild intellectual disability.