Background: Acetabular dysplasia associated with deformity of the proximal part of the femur can result in hip dysfunction and degenerative arthritis in young adults. The optimal method of surgical correction for these challenging combined deformities remains controversial. Methods: We retrospectively analyzed twenty-four hips in twenty patients who underwent a Bernese periacetabular osteotomy, which was done with a proximal femoral valgus-producing osteotomy in thirteen hips, for the treatment of acetabular dysplasia associated with proximal femoral structural abnormalities. The average age of the patients at the time of surgery was 22.7 years, and the average duration of clinical follow-up was 4.5 years. The Harris hip score and overall patient satisfaction with surgery were used to assess hip function and clinical results. Plain radiographs were used to assess the correction of the deformity, healing of the osteotomy, and progression of degenerative arthritis. Results: The mean Harris hip score increased from 68.8 points preoperatively to 91.3 points at the time of the most recent follow-up (p < 0.0001). Sixteen patients (nineteen hips) had an excellent clinical result, and one patient (one hip) had a good result. Two patients (two hips) had a fair result, and one patient (two hips) had a poor result. Twenty-two of the twenty-four hips improved clinically. There was an average improvement of 27.6° in the lateral center-edge angle of Wiberg (p < 0.0001), an average improvement of 33.1° in the anterior center-edge angle of Lequesne and de Seze (p < 0.0001), and an average improvement of 16.5° in the acetabular roof obliquity (p < 0.0001). The hip center was translated medially an average of 6.3 mm (p = 0.0003). The Tönnis osteoarthritis grade was unchanged in twenty hips, progressed one grade in three hips, and progressed two grades in one hip. There were three major technical complications. At the time of the most recent follow-up, none of the hips had required total hip arthroplasty. Conclusions: The combination of acetabular dysplasia and proximal femoral deformities presents a complex reconstructive problem. The range of motion and radiographic assessment of the hip are major factors in the selection of patients for surgery. In selected patients, the periacetabular osteotomy combined with concurrent femoral procedures, when indicated, can provide comprehensive deformity correction and improved hip function. Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.