Adverse childhood experiences (ACEs) are associated with greater prevalence of cardiovascular disease and altered acute stress reactivity. The current study investigated the effect of ACEs on hemodynamic and autonomic responses to orthostatic stress imposed by 60° head-up tilt (HUT) in young adults. 226 healthy young adults (age = 22.6 ± 1.5 years; n = 116 female) without cardiovascular disease participated and had complete data. Participants underwent supine blood pressure (BP), R-R interval (RRI), cardiac output (CO), total peripheral resistance (TPR), and cardiovagal baroreflex sensitivity (cvBRS) testing followed by a transition to 60° HUT where measures were reassessed. Childhood adversity exposures were assessed based upon categorical exposure and non-exposure to childhood household dysfunction and maltreatment, and < 4 and ≥ 4 types of ACEs. Significantly greater increases in SBP (p < 0.05), DBP, MAP, and TPR (p < 0.01; all) following 60° HUT were observed in individuals with ≥ 4 compared to those with < 4 types of ACEs. Attenuated decreases in RRI and cvBRS were observed in those with ≥ 4 types of ACEs (p < 0.05). Experiencing ≥ 4 types of ACEs was associated with augmented BP and TPR reactivity and a blunted decrease in cvBRS in response to 60° HUT in young adults. Results suggest a reduced vagal response to orthostatic stress is present in those who have experienced ≥ 4 types of ACEs which may promote autonomic dysfunction. Future research examining the sympathetic and vagal baroreflex branches is warranted.