Introduction: Our aim was to determine the psychological and educational impact of the 2017 Las Vegas mass shooting on the graduate medical education (GME) mission within two cohorts of resident physicians and attending faculty at two nearby academic trauma centers. Methods: A cross-sectional survey assessed 55 resident physicians and attending faculty involved in the acute care of the patients from the mass shooting. We measured the psychological impact of the event, post-traumatic growth, team cohesion, social support, and known risk factors for post-traumatic stress disorder (PTSD). Additionally, we assessed the impact of the event on GME-specific tasks. Results: Attending faculty and physicians in training in GME residencies evaluated over 300 penetrating trauma patients in less than 24 hours, and approximately 1 in 3 physicians had a patient die under their care. Despite this potential for psychological trauma, the majority of clinicians reported minimal distress and minimal impact on GME activities. However, 1 in 10 physicians screened positive for possible PTSD. Paradoxically, the minority of physicians who sought psychological counseling after the event (20%) were not those who reported the highest levels of distress. Residents generally assessed the event as having an overall negative impact on their educational goals, while attendings reported a positive impact. Psychological impact correlated inversely with social support and the amount of prior education relating to mass casualty incidents (MCI) but correlated directly with the degree of stress prior to the event. Conclusion: Despite the substantial level of exposure, most resident physicians did not report significant psychological trauma or an impact on their GME mission. Some reported post-traumatic growth. However, a minority reported a significant negative impact; institutions should consider broad screening efforts to detect and assist these individuals after a MCI. Social support, stress reduction, and education on MCIs may buffer the effects of future psychologically traumatic events on physicians in training.