Adverse childhood experiences (ACEs) can influence parenting behaviours and have lasting effects on child development. This study investigated how maternal ACEs affect mind-mindedness during interactions between 69 Brazilian mothers and their six-month-old infants, and the role of stress in this relationship. Maternal vocalisations were coded for appropriate and non-attuned mind-related comments according to the Mind-Mindedness Coding Manual. The number of maternal ACEs was assessed using the CDC-Kaiser ACE Study Questionnaire. Current stress, postnatal depression, depression, anxiety, adverse life events, and resilience were assessed using the Perceived Stress Scale, Edinburgh Postnatal Depression Scale, Depression Scale Patient Health Questionnaire, Generalized Anxiety Disorder, the Inventory of Major Life Events, and the Resilience Scale, respectively. General Linear Models analysed associations between variables. The results showed no direct link between ACEs and mind-mindedness. However, stress moderated the relationship between maternal ACEs and appropriate mind-related comments. These findings suggest that maternal exposure to ACEs affects how mothers interpret their infants' mental states, particularly under stress. Understanding these relationships can guide interventions to support maternal mental health and foster positive parent-infant interactions, potentially preventing the intergenerational transmission of trauma.