As consumers' social and environmental concerns have grown in the last decade, so has interest in eco-fashion. Behind fast-changing fashion trends, the apparel industry generates substantial environmental and resource depletion problems throughout the textile lifecycle. To respond to these trends, fashion designers and merchandisers have been motivated to practice sustainability in design and production. Some sustainable options are available, such as organic fibers and environmentally safe dyes. Still, there are challenges for apparel designers and merchandisers when trying to realize sustainability. To help undergraduate apparel students learn problem-solving approaches to sustainable garment design, a problem-based learning project was created and implemented in an undergraduate design course. In the course, students designed and produced an original sustainable garment. Student feedback following the project was largely positive, with most students indicating they would continue using sustainable practices in future work.Keywords sustainable design, design challenge, apparel design, recycling, post consumer, problem-based learning Sustainability in apparel design is a subject of increasing importance. The apparel industry can create many environmental problems, including large quantities of harmful waste that are generated at every stage of the apparel manufacturing process. Along with increasing global awareness of environmental problems, consumers' awareness of sustainability has risen as well. Consumers are seeking environmentally friendly clothing, and producers are exploring ways to meet these demands while keeping an eye on the bottom line. Though consensus exists within the design world that sustainability is a vital topic to explore, little has been written about how to teach this concept. This study suggests one approach to teaching sustainability concepts to undergraduate university students.