Problem-based learning (PBL) represents a widely recommended best practice that facilitates both student engagement with challenging content and students’ ability to utilize that content in a more flexible manner to support problem-solving. This edited volume includes research that focuses on examples of successful models and strategies for facilitating preservice and practicing teachers in implementing PBL practices in their current and future classrooms in a variety of K-12 settings and in content areas ranging from the humanities to the STEM disciplines. This collection grew out of a special issue of the Interdisciplinary Journal of Problem-Based Learning. It includes additional research and models of successful PBL implementation in K-12 teacher education and classroom settings.