The prevalence of obstructive sleep apnea (OSA) has increased worldwide in recent years, becoming a significant public health concern. One of the most important complications experienced by individuals with OSA is excessive daytime sleepiness (EDS). This study aims to investigate the prevalence of EDS in patients with OSA through a systematic review and meta-analysis. Electronic databases including PubMed, Scopus, Web of Science, Embase, ScienceDirect, and the Google Scholar search engine were systematically searched for studies investigating the prevalence of EDS in people with OSA up to December 2023. Data analysis was conducted using Comprehensive Meta-Analysis software (Version 2), employing a random effects model. The heterogeneity of the studies was assessed using the I² index. In review of 15 studies with a combined sample size of 42,924 individuals found that the global prevalence of EDS in patients with OSA was 39.9% (95% CI: 34.4-45.7). The regression results indicated that as the sample size increased, the prevalence of EDS in patients with OSA decreased (p