The Bernese periacetabular osteotomy is commonly used to treat symptomatic acetabular dysplasia. Although periacetabular osteotomy is becoming a more common surgical intervention to relieve pain and improve function, the strength of clinical evidence to support this procedure for these goals is not well defined in the literature. We therefore performed a systematic review of the literature to define the level of evidence for periacetabular osteotomy, to determine deformity correction, clinical results, and to determine complications associated with the procedure. Thirteen studies met our inclusion criteria. Eleven studies were Level IV, one was Level III, and one was Level II. Radiographic deformity correction was consistent and improvement in hip function was noted in all studies. Most studies did not correlate radiographic and clinic outcomes. Clinical failures were commonly associated with moderate to severe preoperative osteoarthritis and conversion to THA was reported in 0% to 17% of cases. Major complications were noted in 6% to 37% of the procedures. These data indicate periacetabular osteotomy provides pain relief and improved hip function in most patients over short- to midterm followup. The current evidence is primarily Level IV. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.