Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease that is highly heterogeneous in its presentation. This can pose significant challenges for physicians responsible for the diagnosis and treatment of such patients. SLE arises from a combination of genetic, epigenetic and environmental factors. Pathologically, the disease is primarily driven by loss of immune tolerance and abnormal B- and T-cell function. Major organ involvement may lead to significant morbidity and mortality. Classification criteria for SLE have been developed largely for research purposes; however, these are also widely used in clinical practice. Antinuclear antibodies are the hallmark serological feature, occurring in over 95% of patients with SLE at some point during their disease. The mainstay of treatment is antimalarial drugs such as hydroxychloroquine, combined with corticosteroids and conventional immunosuppressive drugs. An increasing understanding of pathogenesis has facilitated a move towards the development of targeted biologic therapies, with the introduction of rituximab and belimumab into clinical practice.