Despite the improvements in accurate and consistent patellofemoral radiographs, sophisticated (and expensive) imaging studies, and arthroscopic diagnostic techniques, patellofemoral disorders remain frequently misunderstood and frustrating to treat for far too many orthopedic surgeons. Diagnostic terms such as “patellar maltracking,” “anterior knee pain syndrome,” and “chondromalacia” continue to appear in the literature without definition and add to the confusion. This article proposes a clinical classification for patellofemoral disorders that should help the comprehension, improve the results of treatment, and best of all, allow comparison of one protocol or outcome study with another. A major feature of this classification is the recognition that a developmental and familial abnormality, patellofemoral dysplasia, is the etiology for most patellofemoral disorders. Equally important is the assignment of chondromalacia patellae to a secondary position, for the most part. Other causes of anterior knee pain and disability are included to complete the classification.