Background: COVID-19 outbreak is likely to cause psychological problems, such as anxiety, depression, and stress; which may negatively influence one's glycemic control. The pandemic could increase the prevalence and change in nature of diabetes among people living in countries affected by it. The aim of this review is to clarify the blurred areas and types of relationship between diabetes, psychiatric disorders, and COVID-19 pandemic. Methods: Literature reviews and evidence-based researches were studied using PubMed and Google Scholar for the following keywords: "COVID-19", "SARS-CoV-2", "diabetes", "epidemiology", "pathophysiology", "ACE2", "manifestation”, “immune system”, “link between diabetes and psychiatric illnesses”, and "treatment with antipsychotics and antidepressants”. Results revealed that there is a casual mutual relationship between DM and psychiatric disorders. Furthermore, there is a bidirectional relationship between DM and the vulnerability of acquiring COVID-19 infection. Additionally, DM and SARS-CoV-2 infection worsen each other, thus, diabetics are more likely to develop severe COVID-19. Conclusion and Recommendation: It is recommended that physicians and health care providers counsel their patients that the risk of DM can be significantly reduced by lifestyle changes including diet and exercise. Additionally, a range of psychological interventions, and mandatory vaccinations against COVID- 19 when dealing with diabetic patients.