Systemic lupus erythematosus (SLE) rarely presents with massive ascites secondary to severe peritonitis before the occurrence of major diagnostic features. We described a 13-year-old girl who developed four episodes of severe abdominal pain with massive ascites. During the first episode, the patient experienced deterioration with massive ascites over a 3-day period, after a 3-month history of intermittent abdominal pain. This episode resolved under conservative treatment. During the second episode, her acute abdominal findings mimicked appendicitis or gynecologic emergency. An exploratory laparotomy was initially planned, but not performed. Thrombocytopenia postponed the surgical intervention and led to further investigation. Autoimmune studies confirmed SLE and prompted steroid therapy, which rapidly improved her painful ascites and spared an unnecessary operation. After improvement of peritonitis with ascites, and following discharge, other major clinical features of SLE ensued. The third episode of peritonitis with massive ascites responded well to steroid pulse therapy. The fourth episode of ascites was accompanied by intracranial hemorrhage that led to her death. To the best of our knowledge, this is the first case report of recurrent peritonitis with massive ascites as the initial and major manifestation of SLE in a pediatric patient.