Among various sustainable clothing design strategies, transformable design can encourage people to adopt sustainable fashion behaviors; a versatile garment can be worn in many ways. However, there is a lack of research on prom dresses, which have one of the shortest lifecycles among clothing items since they are usually only worn once. This research investigated consumers' expectations and preferences regarding the changeable design functions of transformable prom dresses related to their shopping orientations. Data were collected from U.S. female college students using an online survey tool. There were significant differences in the reasons given by consumers for the limited use of prom dresses, their design and functional elements, their preferences in the design elements of transformable dresses, and their intention to purchase transformable dresses. The findings can benefit apparel designers and fashion businesses when developing design strategies that can help encourage sustainable fashion behaviors in consumers and enhance their sustainable apparel consumption practices.