Critical incidents (CIs) occur in most schools and school communities. School counselors engage in critical incident response by providing emotional support and response strategies to help students and staff regain a sense of normalcy and emotional safety, and by offering ongoing support. Therefore, this study investigated the impact that involvement in CI response has on school counselor wellness, self-efficacy, and burnout, and the benefits of postvention support in addressing these impacts. It also examined the current extent of postvention supports offered to school counselors. It focused on school counselor response to CIs related to targeted violence, student death by suicide, and environmental disasters. This systematic literature review investigated 90 published research articles that fit the eligibility criteria for this study. It identifies trends that contribute to school counselor burnout and decreased self-efficacy, including a lack of postvention support, insufficient time allocated for self-care, the need for standardized training in CI response duties, and the necessity to increase awareness of the signs and symptoms of burnout in the aftermath of CI events. In contrast, the study found that decreased self-efficacy and symptoms of burnout are mitigated when school counselors receive the time and encouragement to engage in self-care and authentic clinical supervision. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]