BACKGROUND: Diabetes mellitus, a chronic multi-systemic disease affecting various organs, may negatively influence health-related quality of life (HRQoL) and oral health-related quality of life (OHRQoL). This study aimed to investigate this association in a cross-sectional sample of Iraqi Kurdish diabetic patients. METHODS: Two hundred eighty-five type 2 diabetic patients participated in the survey. The EuroQol-5 Dimensions-5 Levels (EQ-5D-5L) and the Oral Health Impact Profile-5 (OHIP-5) instruments were used to measure HRQoL and OHRQoL, respectively. RESULTS: For the HRQoL, 75%, 64%, 46%, and 20% of the participants reported "some" problems in the fields of pain/discomfort, anxiety/depression, mobility, and interruption in usual activities, respectively. Concerning the OHRQoL, difficulty in chewing, finding less flavor in food, oral/dental pain, uneasiness about appearance, and difficulty in doing usual activities were the most complained fields of OHRQoL in 35%, 30%, 29%, 25%, and 20% of the patients respectively. Women had significantly worse HRQoL and OHRQoL compared to men. There was a positive, directly proportional, and significant correlation between HRQoL and OHRQoL (Pearson correlation test = 0.455, = 0.000). CONCLUSION: Sex, income, duration of diabetes, and smoking were the predictive modifying factors for both HRQoL and OHRQoL. From a public health point of view, raising health awareness is urgently needed among Iraqi diabetic patients for better diabetes management, a healthier lifestyle, and regular oral hygiene measurements.