Aim and background: Diabetes mellitus is a long-term systemic metabolic disorder that can affect oral and overall health, while gingivitis is a clinical condition characterised by gum inflammation. Diabetes and gingivitis have a significant impact on a considerable number of people globally, leading to public health concerns. Chronic diabetes profoundly impacts gingivitis. Increased inflammation, reduced immune function, delayed wound healing, and persistent hyperglycaemia promote the growth of microbes that make people with diabetes susceptible to gingivitis. Bangladesh has encountered substantial obstacles in addressing health disparities, particularly between rural and urban regions. The study explores the intricate relationship between gingivitis and diabetes, including their reciprocal effects. Materials and methods: This study examined a sample of 510 community members who participated, and 415 met the inclusion criteria by focusing on certain periodontal outdoor patients at medical colleges and dental clinics in Dhaka and Chattagram districts aged 35–70 years. The interviews obtained initial data using a standardised questionnaire. The selected group had diabetes with or without gingivitis. An observational study was conducted to assess diabetic patients in both urban and rural areas. Every checkup examined the diabetes blood profile of the patients and assessed a detailed oral examination, taking into account factors such as probing pocket depths and tooth attachment. Socio-economic characteristics, anthropometric characteristics, and consumption habits data were also used to determine the patient's dietary diversity. The relationship between gingivitis and diabetes was examined using appropriate statistical methods. Results: Of the total participants, 92.8% exhibited symptoms of gingivitis. In contrast, 7.2% of participants showed no symptoms. Gingivitis was 4.735 times more prevalent in men (p = 0.009) and had a significant gingival index (p = 0.009) after adjusting for confounding variables; gingivitis impact is significantly associated with diabetes duration (p = 0.001), residence in rural areas (p = 0.001), blood glucose levels (p = 0.035), and dentist visits (p = 0.021); moreover, gingivitis decreased by 81.7% with insulin administration (p < 0.001). In contrast, education and gingival colour do not affect gingivitis. Conclusion: The present findings indicate a notable correlation between diabetes and an elevated prevalence of gingivitis in rural areas. This study suggests periodontal care for chronic diabetes.