Background <p>Post-traumatic stress disorder (PTSD) is a debilitating condition that arises after exposure to a traumatic event and leads to significant impairment in daily functioning if left untreated. Economic evaluations are essential for understanding the comparative value of PTSD treatments and ultimately supporting their implementation. Several model-based economic evaluations exist in this area; however, these can differ in their methodological approaches and parameter inputs, which can influence conclusions drawn.</p> Objective <p>This systematic review aimed to explore model structures and parameter inputs employed in model-based economic evaluations of PTSD treatment.</p> Methods <p>A literature search was carried out in the following databases: MEDLINE, PsycINFO, SCOPUS, Econlit, CINAHL, Web of Science Core Collection, and Cochrane Collaboration Library between 1 January 2000 and 1 May 2025. Studies were eligible if they presented a full economic evaluation of a treatment for PTSD using a decision-analytic model. Data relating to the model structure and parameter inputs were extracted and quality assessment was conducted.</p> Results <p>This review identified 14 model-based studies, of which two used decision trees, six used a Markov model, four used a combined decision tree and Markov model, and two used an agent-based model. There was significant variation across model parameters, including in disease conceptualisation and progression, data sources utilised, assumptions reported, and costs included. The quality assessment revealed the following key areas of concern: insufficient consideration of methodological uncertainty and heterogeneity, internal consistency, and incorporation of relevant disease and intervention characteristics.</p> Conclusions <p>This paper highlights important variations in current model-based economic evaluations of PTSD treatment. Future work should seek to generate evidence to support consistency in future economic evaluations of PTSD treatment options.</p>