The use of data-based decision making is critical in any classroom, but especially in special education settings. The Teacher's Guide to Action Research for Special Education in PK-12 Classrooms describes the basic concepts of action research and how this process can support student success in the classroom and beyond. This practical, approachable, and concise guide provides case studies, vignettes, student learning objectives, and review exercises to help teachers understand how to effectively use the action research process to identify and evaluate evidence-based interventions, with explicit connections to legally mandated IEP planning, implementation, and evaluation processes.