This study investigated the proportions and clinicopathological presentations of oral candidal lesions in type 2 diabetes mellitus (DM) patients attending the Diabetic Clinic at Teaching Hospital Peradeniya; Sri Lanka. A descriptive cross-sectional study was conducted on 355 DM patients aged over 18 years who had been receiving treatment for at least one year. Clinical photographs and periodic acid–Schiff (PAS)-stained cytological specimens confirmed diagnoses. Oral candidal lesions were found in 17.6% of patients; with Denture Stomatitis (4.0%), Erythematous Candidiasis (3.4%), Pseudomembranous Candidiasis (3.1%), and Chronic Hyperplastic Candidiasis (2.8%) being the most common types. Notably; all lesions were identified as incidental findings. Erythematous Candidiasis was more frequently noted among individuals older than 60 years (p = 0.041); while Denture Stomatitis was more common with higher glycemic levels (>140 mg/dL) (p = 0.045). Males were significantly more susceptible to oral candidal lesions (p = 0.002); except for Pseudomembranous Candidiasis and Denture Stomatitis; which were more frequent in females. Smoking (p = 0.005) and betel quid chewing (p = 0.008) were also identified as significant risk factors. Binary logistic regression revealed that males (OR = 3.160) and denture wearers (OR = 2.348) had a higher likelihood of developing oral candidal lesions. Despite the relatively low prevalence; routine oral examinations are recommended for early detection and management; ensuring better oral health in this at-risk population.