Parental reflective functioning (RF), the ability to consider the child’s behavior as a function of mental states (cognitions, emotions), is theorized to promote emotion regulation in children via its positive impact on parenting sensitivity. Using a sample of mothers and toddlers (N = 151 dyads; 41% Latinx; 54% girls; M
Age = 21 months; SD
= 2.5 months), we measured mothers’ self‐reported RF (high RF = low certainty/high interest–curiosity/low prementalizing), toddlers’ distress during a standardized challenging behavioral task (toy removal), and three methods of children’s coping with distress. Then, we tested whether RF moderated the association between children’s observed distress and coping during the task (mother‐directed adaptive coping, task‐directed adaptive coping, maladaptive aggression) as an index of emotion regulation. Although RF was not associated with toddlers’ distress, indices of RF moderated the associations between distress and coping. As maternal RF increased, the positive association between toddler distress and mother‐oriented behavior increased, whereas the association between toddler distress and child aggression decreased. Findings were present only for certainty of mental states, whereas no effects were present for prementalizing or interest/curiosity. We discuss these findings in terms of their contributions to theory regarding parent–child relationships, maternal RF, and child emotion regulation.