Twenty-first century educators are faced with new dilemmas, as well as new opportunities. In response to the increasing racial, cultural, and linguistic diversity of students, some school districts and states have implemented policies mandating particular curriculum. However, evidence increasingly shows that teachers who are effective in diverse classrooms are adaptive and responsive rather than strictly adhering to scripted curriculum. One proposed solution is preparation to conduct practice-based research as part of teaching. Practice-based research is a method of studying ones’ own teaching that draws on action research, design-development research, and transformative research. As a method through which teachers define questions, explore solutions, and share successes in professional communities, practice-based research holds tremendous potential to support teachers in diverse classrooms as they work to teach in culturally sustaining ways despite external pressures. This chapter begins with the history of action research and the tradition of teachers conducting research on their practice. Then, examples of practice-based research in literacy teacher education settings from a review of the research literature are provided to demonstrate the challenges, opportunities, and design features for this work. The chapter concludes with recommendations for teacher education policies, for teacher educators, and for practice.