Parents have the opportunity to influence the development of their children’s emotion regulation skills in a variety of capacities throughout childhood and into adolescence. Only recently have we begun to explore the physiological nature of this effect and implications for the influence of social factors on individual regulation of emotion in children. Also not well understood is how contextual and experiential factors influence this relationship by impacting emotional regulation skill development in children; e.g., parents’ experiences of trauma, loss, and stress may affect parenting behavior and child emotional and behavioral outcomes. To further advance our understanding, the present pilot study investigated how children, ages 9 to 14 years old, and their primary female caregivers (N = 41 dyads) respond physiologically to affective challenge, experienced both independently and jointly. Using a community sample, we examined mother and child respiratory sinus arrhythmia (RSA) while viewing a positive and negative video clip (task) either alone or jointly (condition). Further, we explored the influence of self-reported trauma/adversity experiences and symptoms and quality of parenting on RSA response in the dyads. Results indicate caregiver’s RSA responses were lower across conditions but demonstrated greater increases during the joint sessions than their children. Also, child and caregiver characteristics played a complex role; e.g., caregivers were more likely to increase RSA when with their child if they perceived their child to be suffering greater symptoms of trauma exposure. Caregivers may be suppressing their own arousal to play a regulatory role for the benefit of their children.