Background: Since early May 2022, outbreaks of Monkeypox (Mpox) cases have emerged and become a global concern. Studies exploring the gastrointestinal (GI) and/or liver manifestations of Mpox are still very limited. This systematic review and meta-analysis is the first to summarize the GI manifestations reported by Mpox patients. Methods: We searched for Mpox studies published until October 21, 2022, in MEDLINE, EMBASE, SCOPUS, and organization websites. Mpox studies were observational studies that reported at least one of either GI and/or liver manifestations. Meta-analysis was done to obtain the pooled prevalence of GI manifestations in Mpox patients. The quality of included studies was assessed using the NIH Quality Assessment Tool. Results: Overall, 31 studies that reported GI and/or liver manifestations in Mpox patients were included. The five most commonly reported GI manifestations by studies were abdominal pain, anorexia, diarrhea, nausea and/or vomiting, and proctitis. There is a lack of reporting for liver manifestations. The most prevalent GI manifestations in Mpox patients were anorexia (47%; 95%CI 41-53%), followed by nausea and/or vomiting (12%; 95%CI 11-13%), proctitis (11%; 95%CI 11-12%), abdominal pain (9%; 95%CI 8-10%), and diarrhea (5%; 95%CI 4-6%). Conclusion: Anorexia was the most frequently reported GI manifestation in Mpox patients, followed by nausea and/or vomiting, proctitis, abdominal pain, and diarrhea. The presentation of proctitis during the ongoing Mpox outbreak highly suggests a potential for Mpox diagnosis.