Myasthenia gravis (MG) and its animal model experimental autoimmune myasthenia gravis (EAMG) are caused by autoantibodies against nicotinic acetylcholine receptor (AChR) in skeletal muscle. The production of anti‐AChR antibodies is mediated by cytokines produced by CD4⁺ and CD8⁺ T helper (Th) cells. Emerging investigations of the roles of cytokines in MG and EAMG have revealed that the Th2 cell related cytokine interleukin 4 (IL‐4), an efficient growth promoter for B‐cell proliferation and differentiation, is important for anti‐AChR antibody production. IL‐6 and IL‐10 have similar effects. The Th1 cytokine IFN‐γ is important in inducing B‐cell maturation and in helping anti‐AChR antibody production and, thereby, for induction of clinical signs and symptoms. Results from studies of time kinetics of cytokines imply that IFN‐γ is more agile at the onset of EAMG, probably being one of the initiating factors in the induction of the disease, and IL‐4 may be mainly responsible for disease progression and persistance. Even though other Th1 cytokines like IL‐2, tumor necrosis factor α (TNF‐α), and TNF‐β as well as the cytolytic compound perforin do not directly play a role in T‐cell‐mediated help for anti‐AChR antibody production, they are actually involved in the development of both EAMG and MG, probably by acting in concert with other cytokines within the cytokine network. In contrast, transforming growth factor β (TGF‐β) exerts immunosuppressive effects which include the down‐regulation of both Th1 and Th2 cytokines in MG as well as EAMG. Suppressive effects are also exerted by interferon α (IFN‐α). Based on elucidation of the role of cytokines in EAMG and MG, treatments that up‐modulate TGF‐β or IFN‐α and/or suppress cytokines that help B‐cell proliferation could be useful to improve the clinical outcome. © 1997 John Wiley & Sons, Inc. Muscle Nerve, 20, 543–551, 1997