Inclusive instructional design as a concept is based in the foundational work of educational theorists, legislators, and professionals whose work serves to guide the practice of inclusion in education. Laws and policies, both national and international, can strengthen efforts around the world to impact the structures necessary for inclusive education to fully take hold. Both well established and more recent theories in the literature and in practice can soundly ground inclusive instructional design efforts in the larger body of educational research. Organizational frameworks for guiding the implementation of accessible and inclusive practices can address the widely varying needs of learners, inform practice, and help inclusive education efforts to reach their full potential. This chapter offers an encapsulated look at some key laws, theories, and instructional design frameworks that can be applied to help educators better situate themselves as inclusive instructional designers, and serves to inform the content of later chapters in this book. Universal Design for Learning (UDL) is highlighted as an exemplary framework through which the various laws and theories described can be realized through the implementation of its flexible and comprehensive principles and guidelines.