Objectives: This study uniquely examined the impact of maltreatment (without a diagnosis of posttraumatic stress disorder [PTSD]) on physiological responses to a physical and an emotional stressor. The study sample was composed exclusively of women, because men may differ in maltreatment experience and neural regulation of physiological reactivity. Method: Participants were 60 female college students. A significant proportion of the participants reported experiencing childhood maltreatment without a history of PTSD. Participants completed measures assessing psychological and PTSD symptomatology. Heart rate was monitored before, during, and after riding a stationary bike (physical stressor) and viewing a video of a child being maltreated (emotional stressor). Baseline and stressor related patterns of heart rate and respiratory sinus arrhythmia (RSA) were quantified from the beat-to-beat heart rate. Results: Women with maltreatment histories reported more psychological distress and PTSD symptomatology, had lower levels of RSA and faster heart rate, and reacted to the stressors with atypical vagal regulation of RSA and heart rate. Conclusion: Accompanying psychological difficulties, women with maltreatment histories exhibit atypical physiological regulation to stressors consistent with clinical observations of lower thresholds to defensiveness and other manifestations of compromised resilience. The findings are consistent with polyvagal theory, which emphasizes the role of the “vagal brake” in social engagement and coregulation behaviors—features frequently compromised in survivors of emotional and physical abuse. Future research should investigate whether these features of atypical autonomic regulation are lead indicators of mental and physical health risks and whether these features can be reversed.