BACKGROUND: The surgical treatment of acetabular fractures relies on the understanding of fracture architecture and their classification. The Judet and Letournel classification has been the cornerstone in understanding and treating acetabular fractures. Recently, there has been growing evidence of discrepancies and incompleteness in the Judet and Letournel classification, adversely affecting its clinical use. This study describes a novel comprehensive classification system that will direct surgical approach and fixation methods. METHODS: A retrospective study of patients with acetabular fractures treated at a level-I trauma center also serving as a referral center for acetabular fractures was performed. Fractures were classified according to both the novel and Judet and Letournel classification systems. The novel classification developed integrates the displacement vector (posterior, superomedial, or combined) and the fractured anatomic structures (anteroposterior wall, pelvic brim, iliac wing, quadrilateral plate, and ischium). Furthermore, postoperative malreduction was evaluated on the basis of intra-articular gap measurements in either anteroposterior or Judet oblique views. RESULTS: The study included 229 patients with acetabular fractures treated between 2007 and 2016. The mean patient age (and standard deviation) was 46.7 ± 21.75 years, and 172 patients (75.1%) were surgically treated. According to the novel classification system, the posterior displacement vector group included 60 patients, the superomedial displacement vector group included 130 patients, the combined displacement vector group included 36 patients, and 3 patients were unclassified by the new system. Forty-six patients (20.1%) could not be classified by the Judet and Letournel classification. Pelvic-brim fracture patterns were described as along the pelvic brim, across the pelvic brim, or comminuted. The quadrilateral plate primary fracture line was shown to be perpendicular to the pelvic brim. The selection of surgical approach and fixation methods depends on the fracture type. CONCLUSIONS: This study presents a novel classification system for acetabular fractures. It offers a complete classification system, encompassing nearly all fracture patterns. As the selection of surgical approach and fixation methods depends on fracture classification and understanding, the novel classification system can aid the surgeon with decision-making.