Streptococcus anginosus can be frequently isolated from brain abscesses, but is a rare cause of the liver, lung, and deep tissue abscesses. In this report, we present a patient with subdural empyema, brain abscess, and superior sagittal cerebral venous thrombosis as complications of rhinosinusitis whose purulent empyema sample yielded S. anginosus. A 13-year-old female patient was referred to our pediatric intensive care unit with altered mental status, aphasia, and behavioral change. On a brain computed tomography scan, subdural empyema extending from the left frontal sinus to the frontal interhemispheric area and left hemispheric dura was detected. Intravenous ceftriaxone, vancomycin, and metronidazole treatments were started. Subdural empyema was surgically drained. Postoperative brain magnetic resonance venography imaging showed superior sagittal sinus thrombosis. Cultures obtained from purulent empyema sample revealed S. anginosus. On the third day of hospitalization, a brain computed tomography scan showed brain edema, especially in the left hemisphere and significantly increased subdural empyema that had been previously drained. She was reoperated and decompressive craniectomy was performed. On the fifth day, partial epileptic seizures occurred. Brain magnetic resonance imaging showed a brain abscess on the interhemispheric area. The magnetic resonance imaging findings of abscess formation improved on 30th day and she was discharged on the 45th day after the completion of antibiotic therapy.