Background: Intensive care unit (ICU) nurses are at an increased risk of post-traumatic stress disorder (PTSD) due to their stressful work environment. Using the Walker and Avant conceptual analysis method, we sought to review the literature to better understand PTSD as it pertained to ICU nurses and its impact on their lives, patient care, and health care organizations. Methods: For the review, we searched the Cumulative Index of Nursing and Allied Health Literature (CINAHL), PubMed, and PsycINFO. The keyword searches included the terms “post-traumatic stress disorder” AND “psychological stress” AND “intensive care unit nurses.” Abstract and full text reviews were conducted. Ten articles met our inclusion criteria of being published in the past 10 years (2010–2020), peer reviewed, written in English, and referred specifically to PTSD and psychological stress in ICU nurses. Findings: Antecedents for PTSD in ICU nurses are their stressful work environment, where exposure to traumatic events is experienced, and a lack of support from their manager, coworkers, and organization. Defining attributes for ICU nurses with PTSD included reexperiencing, avoidance, negative alterations in cognition and mood, and hyperarousal. Consequences identified included burnout, job dissatisfaction, and the intention to leave their job. The conceptual definition of PTSD in ICU nurses was illustrated by the attributes, antecedents, consequences, model case, empirical referents, and by the negative impact on the nurse, patients, and the health care organization. Conclusion/Application to Practice: Hospital administrators, nurse managers, and occupational health nurses should ensure that policies and interventions are in place to recognize and reduce the risk of PTSD among ICU nurses.