Background: The number of refugees worldwide is at an all-time high. The majority of refugees experience traumatic events and the death of loved ones. The 11th revision of the International Statistical Classification of Diseases and Related Health Problems now includes prolonged grief disorder and complex posttraumatic stress disorder and a revised guideline for posttraumatic stress disorder, and a joint overview of these stress-related disorders in refugees is needed. We therefore conducted a systematic review to determine prevalence rates, comorbidities, and associated factors. Method: We systematically searched PubMed, Web of Science, and PsycArticles to identify studies published in English that reported prevalence rates, predictors or associated factors, and/or comorbid mental disorders of at least one of the disorders in a refugee population. The selection process was based on the PRISMA guidelines, and independent raters assessed selection criteria and study quality. Results: 36 studies that were published between 2008 and 2022 met inclusion criteria. Most of the studies were of high quality. Pooled prevalence for posttraumatic stress disorder was 21.3%, and 36.8% for complex posttraumatic stress disorder. Prevalence rates ranged from 6% to 54% for prolonged grief, 0.4% to 80% for posttraumatic stress disorder, and 3% to 74.6% for complex posttraumatic stress disorder. Posttraumatic stress disorder was among the most frequent comorbidities for prolonged grief disorder and depressive symptoms co-occurred frequently for all three disorders. Sociodemographic variables, trauma exposure, and loss characteristics were associated with higher symptom severity. Postmigration factors played an important role in prolonged grief and complex posttraumatic stress disorder. Conclusion: Despite substantial variations in prevalence rates, the review underscored very high prevalence rates of stress-related disorders included in ICD-11 among refugees. The identified associated factors point to subgroups of refugees that may be particularly at risk and provide implications for specific interventions and policy changes. Future research should perform longitudinal investigations, emphasize culturally sensitive assessment, and study disorder-specific mechanisms.