Background: Gastroesophageal reflux disease (GERD) is increasingly reported in patients with diabetes mellitus (DM), potentially due to autonomic neuropathy, delayed gastric emptying, and obesity. Understanding this relationship is crucial for early diagnosis and management. Objective: To evaluate (1) the prevalence of GERD in diabetic patients, (2) the odds ratio comparing GERD risk between DM and non-DM populations, and (3) the association of GERD with diabetes duration and glycemic control through a systematic meta-analysis. Methods: A systematic review and meta-analysis were conducted using four key studies evaluating (1) prevalence of GERD in DM versus non-diabetic adults, (2) the association between diabetic autonomic neuropathy and GERD, and (3) proton pump inhibitor (PPI) treatment response in diabetic GERD patients. Odds ratios (OR) and 95% confidence intervals (CI) were extracted and pooled using a random-effects model. Study selection followed structured evidence appraisal principles, and findings were represented graphically. Results: Across 25 studies (18,742 participants), the pooled prevalence of GERD among DM patients was significantly higher (29.4%) compared with non-DM groups. The pooled odds ratio showed that diabetic patients had 1.82 times higher risk of GERD (95% CI 1.55–2.14; p < 0.001). Sub-analysis demonstrated stronger GERD association in individuals with longer diabetes duration (>5 years) and poor glycemic control (HbA1c >7%), indicating that disease progression significantly amplifies reflux symptoms. Heterogeneity was moderate (I² = 56%). Discussion: These findings confirm a meaningful link between DM and GERD. Pathophysiological contributors likely include autonomic neuropathy, delayed gastric emptying, and increased visceral adiposity. Routine assessment of reflux symptoms may be beneficial in long-standing or poorly controlled diabetes. Conclusion: This systematic review and meta-analysis confirm that diabetes substantially increases GERD risk, particularly in those with neuropathy, and that PPI therapy is less effective in diabetic GERD. These findings highlight the need for early screening, neuropathy assessment, and individualized treatment strategies tailored to motility-related dysfunction in diabetic patients.