Guillain‒Barré syndrome (GBS) is a group of acute immune-mediated disorders in the peripheral nervous system. Both infectious and noninfectious factors are associated with GBS, which may act as triggers of autoimmune responses leading to neural damage and dysfunction.Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its vaccines as well as flaviviruses have been associated with GBS, although a robust conclusion has yet to be reached. Immunomodulatory treatments, including intravenous immunoglobulins (IVIg) and plasma exchange (PE), have long been the first-line therapies for GBS. Depending on GBS subtype and severity at initial presentation, the efficacy of IVIg and PE can be variable. Several new therapies showing benefits to experimental animals merit further investigation before translation into clinical practice. We review the state-of-the-art knowledge on the immunopathogenesis of GBS in the context of coronavirus disease 2019 (COVID-19). Immunomodulatory therapies in GBS, including IVIg, PE, corticosteroids, and potential therapies, are summarized.The association with SARS-CoV-2 remains uncertain, with geographical differences that are difficult to explain. Evidence and guidelines are lacking for the decision-making of initiating immunomodulatory therapies in mildly affected patients or patients with regional subtypes of GBS.