Patients with endogenous or exogenous glucocorticoid (GC) excess exhibit a range of side effects, including an increased risk of infections. Via both mechanism, immune impairments and cardiometabolic concomitant diseases, patients with GC excess could be at increased risk for COVID-19. The impact on incidence and outcome of a SARS-CoV-2 infection in this population are not yet completely clear. This review aims to compile the data available to date and to discuss the existing literature on this topic. Further we highlight potential effects of SARS-CoV-2 on the hypothalamic-pituitary-adrenal axis as well as the influence of endogenous or exogenous GC excess on SARS-CoV-2 mRNA vaccination. There is growing evidence suggesting an increased risk of infection and severe outcome in patients with high-dose GC therapy after contracting SARS-CoV-2. The few data and case reports on patients with endogenous GC excess and SARS-CoV-2 infection point in a similar direction: chronic GC excess seems to be associated with an unfavorable course of COVID-19. Whether this is mainly a primary immune-mediated effect, or also triggered by the many GC-associated comorbidities in this population, is not yet fully understood. Patients with endogenous or exogenous GC excess should be considered as a vulnerable group during the SARS-CoV-2 pandemic. Regardless of the cause, vaccination and consistent surveillance and control of associated comorbidities are recommended.