Anxiety is reported to be common and serious among men who have sex with men (MSM). A growing number of researchers focus on MSM's anxiety and reported their severity, while the estimate results vary substantially between studies. The objective of this study is to evaluate the pooled prevalence of anxiety or anxiety disorders among MSM worldwide. This systematic review and meta-analysis protocol will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA-P) guidelines. Studies will be searched from English and Chinese electronic databases. Observational studies, longitudinal studies, and controlled trials reporting the prevalence of anxiety or anxiety disorders among MSM will be included. Two reviewers will independently screen all the studies and extract data. Quality appraisal will be conducted using the Joanna Briggs Institute's (JBI's) critical appraisal checklist for reporting prevalence data. Meta-analysis will be implemented with a random-effect model which will evaluate pooled prevalence of anxiety with 95% confidence intervals (CI). Subgroup analysis will be conducted among different regions, sampling methods, data collection methods, MSM characteristics, measures used to assess anxiety and its cut-off. This review will contribute to a great understanding of anxiety among MSM worldwide. The findings will help relative policymakers and researchers develop effective measures and interventions for reducing the burden of anxiety morbidity among this population.