Systemic lupus erythematosus (SLE) is a systemic disease which affects mainly young females and can cause lifethreatening conditions. Pleural effusion can occur in SLE patients and usually tends to be mild and bilateral. This report aims to highlight the clinical presentation and medical management of massive unilateral pleural effusions in SLE patients. Here we report a 35-year-old female diagnosed with SLE for six years. She presented with shortness of breath, severe pleuritic chest pain, and fatigue. Her clinical examination showed signs of massive pleural effusion on the right side which was confirmed later by a chest x-ray and computer tomography of the chest. An echocardiography and abdominal ultrasound indicated no pericardial effusion and no ascites. A pleural fluid analysis showed exudative fluid. Sputum culture and polymerase chain reaction on blood sample for Mycobacterium tuberculosis were negative. She was also edematous and pale but not cyanotic or jaundiced. The treatment included blood transfusions, antibiotics, rituximab, azathioprine, and hydroxychloroquine. The pleural effusion responded well to rituximab, and she was discharged after two months in good condition.