Hepatitis B virus (HBV) infection is one of the most common diseases, and approximately two billion people are infected with HBV in the world. Until recently, hepatitis B surface antigen (HBsAg)-negative patients, carrying hepatitis B surface antibody (anti-HBs) and/or hepatitis B core antibody (anti-HBc), have been considered to have achieved the resolution of HBV infection; however, among those patients, the reactivation of HBV has been increasingly reported after chemotherapy, hematopoietic stem cell transplantation, or immunosuppressive therapy. The reactivation of HBV can cause lethal hepatitis called de novo hepatitis B. Therefore, serological examination for HBV infection before starting immunosuppressive therapy is now recommended for all patients with rheumatic diseases. Systemic lupus erythematosus (SLE) is one of the autoimmune diseases characterized by the production of autoantibodies and usually requires immunosuppressive therapy. However, to date, a few reports are available regarding the prevalence and time course of HBV infection in patients with SLE under immunosuppressive therapy. In this review, we update the prevalence and time course of HBV infection in lupus patients using our data and previous papers available, with a special emphasis on occult HBV infection and a decrease of HBV-related antibodies (anti-HBs and anti-HBc) under immunosuppressive therapy. This review also highlights the screening and management of HBV infection currently recommended and the potential role of HBV infection in the pathogenesis of SLE. Throughout the present review, we recommend the pretreatment screening for HBV infection in patients with SLE as well as patients with other rheumatic diseases.