Background <p>Gastroesophageal reflux disease (GERD) and temporomandibular disorders (TMDs) are multifactorial conditions characterized by complex interactions among biological, psychological, and behavioral factors. GERD is increasingly recognized as a systemic disorder with multiple extra esophageal manifestations, while TMD represents a major source of chronic orofacial pain worldwide. This study aims to examine the association between GERD and TMD risk in a large-scale, population-based cohort.</p> Methods <p>This nationwide cohort study used data from the Korean National Health Insurance Service. We included 195,533 adults aged ≥ 19 years who completed health screenings between 2010 and 2011. GERD was identified using diagnostic codes and two or more prescriptions of acid-suppressive medications for ≥ 2 weeks. Participants with prior TMD, bruxism, dental trauma, malignancy, or reflux-inducing medications were excluded. A 1:3 propensity score matching was performed to reduce confounding. The primary outcome was the incidence of TMD. Multivariable Cox regression models were used to estimate adjusted hazard ratios with a 95% confidence interval.</p> Results <p>After matching, 40,755 individuals with GERD and 115,242 controls were included. The incidence of TMD was higher in the GERD group than in the control group (6.65 vs. 4.31 per 1,000 person-years). GERD was associated with an increased risk of TMD, with an adjusted hazard ratio of 1.23 and a 95% confidence interval of 1.15–1.31. Kaplan–Meier analysis showed significantly lower TMD-free survival in the GERD group.</p> Conclusions <p>GERD was significantly associated with increased TMD risk. Screening for TMD symptoms among individuals with GERD may support early detection and improved care.</p> Graphical Abstract <p></p>