In this paper, we applied problem-based learning (PBL) in four required courses in apparel design and merchandising programs and reported the PBL projects and student learning assessment. In the Fall 2016 semester, four courses, i.e., Seminar on Fashion Sustainability, Fundamentals of Textiles I, Fundamentals of Textiles II, and Advance Apparel Product Development, were revised and taught to include PBL projects. All of the PBL projects were related to sustainability and described in the paper. The student learning outcomes were evaluated using pre- and post-quizzes and PBL project evaluation rubrics. Students averaged a score of 5 on the pre-quiz (50%) and increased to an average score of 8 (80%) on the post-quiz, demonstrating short-term gains in their sustainability content knowledge. The average PBL project scores were between 89% to 99% in the four courses, which overwhelmingly demonstrated the students' analytical, problem solving, and decision-making skills in the completed PBL projects.