BACKGROUND: The feeling of loneliness is one of the global challenges for immigrants with adverse consequences on mental health. Also, no comprehensive meta-analysis study was found in this regard. Thus, this systematic review and meta-analysis study aimed to investigate the global prevalence of loneliness in immigrants. METHODS: PRISMA guideline was followed to find eligible studies. PubMed, WoS, Scopus, Embase, ScienceDirect, and Google scholar databases were searched systematically using main keywords of Prevalence, Outbreak, Loneliness, Lonely, Immigration, and Immigrants. Following the exclusion of duplicates, primary and secondary screening processes were applied and the qualification of papers was assessed using the STROBE checklist. Random Effect Model was used for data analysis (CMA v.2). The heterogeneity was checked with the I RESULTS: Following the review of 11 eligible studies with the sample size of 166,913 immigrants, the global prevalence of loneliness in immigrants was found 24.7 % (95 %CI:19.5-30.7). Meta-regression analysis also showed that following the increase in sample size and year of paper publication, the prevalence of loneliness in immigrants accelerates significantly (p <
0.05). CONCLUSION: Loneliness among immigrants is an important mental health issue, globally
thus, according to the high rate of immigration in nations, comprehensive management seems necessary by the health care system.