Background A systematic and meta-analysis of the prevalence of anxiety and posttraumatic stress disorder (PTSD) in immigrants was conducted. Methods Based on the keywords, scientific databases were systematically searched to identify articles. The search included the three databases PubMed, Google Scholar and Research Gate until June 2020. The analysis was performed to assess the prevalence of anxiety and PTSD; subgroups were examined based on anxiety disorders. Results The prevalence of agoraphobia, PTSD, generalized anxiety disorder (GAD), panic disorder, obsessive-compulsive disorder (OCD), social phobia and specific phobia were 4, 25, 9, 4, 3, 5 and 8%, respectively. Conclusions Considering the findings of the present study regarding the significant prevalence of anxiety and PTSD in the immigrant population, it is necessary to pay special attention to the mental health of this population.