Clothing designs can be beautiful. But they are also functional. Fashion’s dual nature sits uneasily in intellectual property law, and its treatment by copyright, trademark, and design patent laws has often been perplexing. Much of this difficulty arises from an unclear understanding of the nature of functionality in fashion design. This Article proposes a robust account of fashion’s function. It argues that aspects of garment designs are functional not only when they affect the physical or technological performance of a garment but also when they affect the perception of the wearer’s body. Generally, clothes are not designed or chosen simply to look good. They are also characteristically designed or chosen to look good on. This approach clarifies the appropriate treatment of fashion design in intellectual property, and it exposes the conceptual limitations of the Supreme Court’s recent copyright decision in Star Athletica, L.L.C. v. Varsity Brands, Inc.