Proximal humerus fracture dislocations, excluding 2-part greater tuberosity fracture dislocations, are rare injuries. Outcomes after open reduction and internal fixation (ORIF) of these injuries have not been well described in the literature. The purpose of this study was to report the radiographic and functional outcomes of patients who underwent ORIF of a proximal humerus fracture dislocation. All skeletally mature patients who underwent ORIF of a proximal humerus fracture dislocation between 2011 and 2020 were identified. Patients with isolated greater tuberosity fracture dislocations were excluded. The primary outcome was American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score at a minimum of 2 years. Secondary outcomes were the development of avascular necrosis (AVN) and reoperation rate. Twenty-six patients met the inclusion criteria. The mean age was 45 years (standard deviation 16), and 77% were men. Median time to reduction and surgery was 1 day (interquartile range [IQR] 1-5). There were 2 (8%) Neer 2-part fractures, 7 (27%) 3-part, and 17 (65%) 4-part fractures. Fifty-four percent (54%) involved the anatomic neck and 31% included a head-split component. Thirty-nine percent (39%) were anterior dislocations. The rate of AVN was 19%. The reoperation rate was 15%. Reoperations included removal of hardware (2), subscapularis repair (1), and manipulation under anesthesia (1). No patients went on to arthroplasty. ASES scores were available for 22 patients (84%) including 4 of 5 patients with AVN. The median ASES score at a mean of 6.0 years postoperatively was 98.3 (IQR 86.7-100, range 63.3-100) and was not different in those with or without AVN (median 98.3 vs. 92.0, P=.175). Only the presence of medial comminution and nonanatomic head shaft alignment on postoperative radiographs were associated with increased risk of AVN. Radiographic rates of AVN (19%) and reoperation (15%) were high in this series of patients undergoing ORIF of proximal humerus fracture dislocations. Despite this, none of the patients required arthroplasty, and patient-reported outcome scores at an average of 6 years postinjury were excellent, with a median ASES score of 98.5. ORIF should be considered as primary method of treatment in proximal humerus fracture dislocations not only in young patients but also middle-aged patients.