Fashion retailers, marketers, and app designers must captivate their dominant consumers: Generation-y women. Nevertheless, existing research and design practice is grounded in older apps and older generations: Generation-x. Through 27 semi-structured interviews, we define generation-y's unique interaction with -and perception of -fashion m-commerce to enhance fashion retailers' ability to design apps targeted at their dominant consumers. We prove that efficiency and convenience drive app engagement, official marketing social media is more effective than friend's social media posts, and interactive design features are irrelevant in purchase motivation. We finish by communicating our findings through six design recommendations, subdivided by market sector.