Background: Diabetes mellitus is a chronic noncommunicable disease characterized by hyperglycemia and is associated with chronic complications affecting the overall quality of life. As of 2017, the prevalence of diabetes in Lebanon is estimated to be 14.6%. Depression is noted to be common among Lebanese citizens, present in around 17.3%. This study aims to investigate the prevalence of depression among the diabetic Lebanese citizens and to study its relationship with poor glycemic control and diabetes complications. Methods: In total, 436 diabetic patients participated in this cross-sectional study. Patients with diabetes mellitus attending several private clinics and health care centers were asked to fill out a well-structured questionnaire developed by an expert. Depression was assessed using Beck Depression Inventory (BDI). The study collected demographic information about the participants including their lifestyles, their last reported glycosylated hemoglobin values, and their reported microvascular and macrovascular complications. Data were collected, entered, and analyzed on SPSS software version 23.1. A descriptive analysis is carried out by calculating the mean and standard deviation for continuous variables and number and percentage for categorical ones. Association between categorical variables is evaluated using a chi-squared test. A P-value of <0.05 is considered to be significant. Results: Depression was prevalent among 28.8% of the patients with diabetes mellitus. The average age of participants was 64.08 years. In total, 280 (64.2%) of the participants were females and the average diabetes duration was 8.89 years. There was no significant relationship found between depression and glycemic control. By contrast, a significant association between retinopathy, nephropathy, and stroke and depression was found. Conclusion: Depression was found to be present among 28.8% of the patients with diabetes mellitus in Lebanon; however, no association was established between depression and glycemic control.