As a result of frequent exposure to trauma, aid workers are at high risk for negative psychological symptoms. Training specifically geared at fostering critical incident self-efficacy in humanitarian aid workers may bolster critical incident self-efficacy as well as general self-efficacy as they relate to experiences of traumatic symptomatology and resilience. Sixty-three aid workers completed questionnaires regarding efficacy, resilience, coping, and posttraumatic stress symptomatology at baseline, and 46 aid workers completed the same measures after the training workshop. Multiple regression analysis indicated that higher levels of self-efficacy related to higher resilience levels. General self-efficacy and critical incident coping self-efficacy (CICSE) were stronger after the training, even when controlling for histories of trauma. Histories of trauma contributed significant variance to CICSE before the training but were insignificant after the training. These findings suggest that aid organizations can support their workers by providing training that promotes resilience through enhancing efficacies.