Background: Gastroesophageal reflux disease (GERD) is a prevalent disorder influenced by the dysfunction of the gastroesophageal junction (GEJ). The gastroesophageal flap valve (GEFV), a key anatomical component, plays a significant role in reflux prevention, yet its clinical relevance remains underexplored. This study evaluates the correlation between GEFV grading, GERD symptoms, and associated endoscopic findings. Methods: A cross-sectional study was conducted at the Department of Endoscopy, Padmashree Diagnostic Centre, Bengaluru, India, involving 201 GERD-symptomatic patients from December 2022 to December 2024. Participants underwent upper gastrointestinal endoscopy, with GEFV grading assessed using the Hill classification. GERD symptom severity was evaluated using the GERD-Q questionnaire, and associations between GEFV grade, esophagitis, hiatus hernia (HH), and GERD-Q scores were analysed using statistical methods, including chi-square tests and ANOVA. Results: Among the participants, 55.2% were female, and 44.8% were male. The prevalence of non-erosive reflux disease (NERD) was 51.2%, while reflux esophagitis was observed in 7.5%. Higher GEFV grades correlated significantly with increased esophagitis (p = 0.001) and HH (p < 0.001). Hill Grade IV was strongly associated with HH (77.8%). GERD-Q scores differed significantly across diagnostic categories (p < 0.001), with reflux esophagitis patients exhibiting the highest scores. Conclusion: GEFV grading is a clinically relevant parameter in GERD assessment, demonstrating significant associations with esophagitis and HH. These findings highlight the importance of GEFV evaluation in GERD diagnosis and management, supporting its role in predicting disease severity and therapeutic response.