Diabetes mellitus is rapidly growing in prevalence around the world. In addition to leading to numerous difficult-to-treat complications, diabetes is associated with worsening mental health and reduced quality of life. Furthermore, having a psychiatric illness or taking certain psychotropic medications increase one’s risk of developing diabetes. While the relationship between diabetes and mental illness has been explored extensively in prior literature, relatively few studies have addressed the link between diabetes and suicide. In this narrative review, the authors describe current knowledge on the associations between suicidality and type 1 diabetes, type 2 diabetes, medication-induced diabetes, gestational diabetes, and diabetic complications. Existing literature suggests that patients with type 1 diabetes or dialysis dependence due to diabetic nephropathy have an especially elevated risk of mortality by suicide compared to the general population. Additionally, there is a bidirectional relationship between depression and type 2 diabetes, contributing to higher suicide rates in these patients as well. Patients with pre-existing psychiatric illness also have increased suicide rates, and current pharmacologic treatment options for mental illness and suicidality cause significant weight gain and metabolic disturbances that can lead to the development or worsening of diabetes. Regular screening for depression and suicidal ideation is recommended for patients with diabetes. Diabetes devices and pharmacologic or non-pharmacologic weight loss strategies may improve mental health and glycemic outcomes in patients with both diabetes and suicidal ideation.