Background: The Bernese periacetabular osteotomy (PAO) is commonly used to surgically treat residual acetabular dysplasia. However, the degree to which function and radiographic deformity are corrected in patients with more severe deformities that have undergone previous reconstructive pelvic or femoral osteotomies is unclear. Questions/purposes: We evaluated hip pain and function, radiographic deformity correction, complications, reoperations, and early failures (conversion to THA) associated with PAO in hips treated with previous reconstructive hip surgery. Methods: We retrospectively reviewed 63 patients who had undergone 67 PAOs after a previous reconstructive hip procedure. We compared preoperative hip scores and radiographic parameters with postoperative values at most recent followup. We recorded complications, need for nonarthroplasty revision surgery, and failures. Minimum followup was 2 years. Results: Five of the 67 hips (8%) were converted to THA between 24 and 118 months. The average followup for the remaining 62 hips was 60 months (range, 24-147 months). The average Harris hip score improved 11 points, and postoperatively, 83% of the hips had pain component scores of greater than 30 (none, slight, or mild pain). Radiographically, there were improvements in lateral center-edge angle (25°), anterior center-edge angle (23°), Tönnis angle (17°), and medialization of the hip center (8 mm). Complications occurred in 13 hips (19%). Seven hips (10%) underwent a subsequent surgical procedure to address residual pain or deformity. Conclusions: PAO performed after previous reconstructive hip surgery improves hip function and corrects residual dysplasia deformities. These procedures are inherently more complex than primary PAO and are associated with a considerable risk of perioperative complications, reoperations, and early treatment failures. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.