While the majority of students in schools tend to respond to effective general academic instruction and proactive schoolwide discipline systems, some continue to exhibit intense and chronic problem behaviors, even in the best schools. For these students, schools are highly variable in their ability and capacity to provide accurate and durable specialized academic and behavioral supports. In these schools, frequent requests are made for assistance to address the specialized needs of these students. The intent of this article is twofold: (a) to provide an overview of the features that characterize a function-based approach to student support, and (b) to introduce the main articles within this special issue, which offer a variety of perspectives and practices related to function-based support at the classroom, school, and district level.