Post-traumatic stress disorder (PTSD) is common among homeless people and is associated with an increased risk of mortality from suicide, medical causes, and drug-related problems. However, there are no previous systematic review and meta-analysis studies that reported the consolidated magnitude of PTSD among homeless people. A literature search was conducted on PubMed, Embase, and Scopus to discover pertinent studies that determined the prevalence of PTSD among the homeless. Articles were evaluated by titles, abstracts, and full-text. Comprehensive meta-analysis software was used to conduct the meta-analysis. Subgroup and sensitivity analysis were performed and Cochran's Q- and the I test were used to assess heterogeneity. The evidence of publication bias was evaluated by using Egger's test and visual inspection of the symmetry in funnel plots. From the total, 19 studies with 20,364 participants across seven countries were included in the final analysis. Our meta-analysis revealed that the pooled prevalence of PTSD among homeless people was 27.38% (95% CI; 21.95-33.57). In our subgroup analysis, we found that the prevalence of PTSD was considerably high as measured by the screening instrument (35.93%) than the diagnostic instrument (23.57% %). The prevalence of PTSD among homeless showed a significant variation by the location of the studies, the instruments used to measure PTSD as well as the quality of the included studies. This review showed that the pooled prevalence estimate of PTSD among homeless peoples was remarkably high (27.38%). Early screening and treatment of PTSD among homeless peoples are warranted to alleviate suffering.