Objective: Aggression is common in patients with schizophrenia and is clinically significant, but its prevalence is inconsistent across studies. This is a meta-analysis of the prevalence of aggression and its associated factors in patients with schizophrenia. Methods: PubMed, EMBASE, PsycINFO, the Cochrane Library, Medline and Web of Science databases were systematically searched. Studies that reported the prevalence of aggression in patients with schizophrenia using the Modified Overt Aggression Scale (MOAS) were included and analyzed using the random-effects model. Results: Fifteen studies with 4855 patients were initially included; of these, 13 studies with 3929 patients were pooled in the final meta-analysis. The pooled prevalence of aggression was 33.3% (95%CI: 21.5%–47.7%); specifically, the estimated prevalence of verbal, property-oriented, auto and physical aggression were 42.6% (95%CI: 17.0%–72.9%), 23.8% (95%CI: 10.1%–46.4%), 23.5% (95%CI: 6.5%–57.7%), and 23.7% (95%CI: 10.4%–45.3%), respectively. Subgroup analyses revealed that different MOAS cut-off values (P < 0.001) and source of patients (inpatients vs. community-dwelling patients) significantly moderated the results (P < 0.001). Meta-regression analyses found that studies published recently reported higher aggression rate, while higher quality assessment score was associated with lower aggression rate (both P < 0.01). Conclusions: This meta-analysis confirmed that aggression is common in schizophrenia patients. Considering the significant clinical risk issues, appropriate treatments and effective management of aggression in this population need to be developed.