Abstract: Extranodal natural killer/T-cell lymphoma (ENKTL) is an Epstein-Barr virus-associated aggressive non-Hodgkin's lymphoma (NHL). It is prevalent in Asia and South America with an aggressive clinical course and a dismal prognosis. Currently, the prognostic models that are commonly used for ENKTL include the International Prognostic Index (IPI), Korean Prognostic Index (KPI), Prognostic Index of Natural Killer Cell Lymphoma (PINK), and Prognostic Index of Natural Killer Cell Lymphoma with Epstein-Barr virus DNA (PINK-E), all of which have some limitations. Positron emission tomography/computed tomography (PET/CT) is a new imaging technique combining anatomical and functional imaging, with the advantages of high sensitivity and specificity, which is essential for diagnosis, staging, efficacy evaluation, and prognosis prediction of various malignant lymphomas. However, the prognostic value of PET/CT in ENKTL remains controversial. Therefore, in this article, we review relevant studies on the prognostic value of pretreatment, interim, and end-oftreatment PET/CT in patients with ENKTL.