Hip dysplasia, in broad terms, is a condition involving joint changes that occur when concentric and stable hip reduction is not achieved during development. Adult dysplasia is in most cases a consequence of treated or untreated hip dysplasia in early childhood. Acetabular changes are characterized by a shallow acetabulum and a change in the acetabular version. Labral and chondral pathologies, ligamentum teres lesions, adaptive changes in the femur and involvement of the perihip muscle group, particularly the abductor muscles, may also accompany the course of the disease. Patients usually present with insidious onset of groin pain and apprehensive complaints, but clinical presentation may vary according to the accompanying pathologies. Direct pelvic X-rays constitute the first step of radiographic evaluation and it is important that they are obtained by appropriate methods for accurate evaluation. Classically, a lateral center-edge angle of less than 20° on an anteroposterior X-ray is the most commonly defined radiographic finding. In addition to the acetabular index, extrusion index, Tönnis angle, acetabular wall indices, femoroepiphyseal acetabular roof index, anterior center-edge angle that can be measured from false profile imaging, computed tomography, magnetic resonance imaging and dynamic ultrasound are also part of the radiological evaluation. Although there is not enough consensus, classification systems have been proposed according to the relationship of the femur to the acetabulum or the three-dimensional localization of acetabular insufficiency.