<p>An association between gastroesophageal reflux disease (GERD) and sleep disorder has been reported. However, the magnitude of this association remains poorly understood. Therefore, we aimed to systematically evaluate this relationship. We conducted a comprehensive search for observational studies in eight databases from their inception to February 28, 2025. The characteristics of each study and pooled risk ratio (RR) with corresponding confidence intervals were calculated. Subgroup analyses were performed to explore sources of heterogeneity. A total of eighteen studies involving 110,417 participants met the inclusion criteria and were included in this meta-analysis. Our findings indicate a statistically significant unidirectional association between GERD and sleep disorder (RR = 2.02, 95% CI 1.71 to 2.37). Subgroup analyses consistently demonstrated an association between sleep disorder and GERD regardless of the diagnostic tools used for either condition (<i>P</i> = 0.32 for GERD diagnosis tools and <i>P</i> = 0.80 for sleep disorder diagnosis tools). Sensitivity analysis indicates that the conclusions are highly stable, and GRADEpro evaluation results have a low level of evidence. This meta-analysis reveals a significant correlation between sleep disorder and GERD. More studies under consistent conditions are needed to validate these findings.</p>