"Response to intervention" (RTI) as a model for boosting student achievement has taken off like wildfire. When it comes to research on how best to implement the process for students in middle and high school, though, the flame abruptly fizzles out. There's little RTI research that is specific to secondary schools, although it has been well studied at the elementary level. But many schools are forging ahead. In Colorado, spurred by a state law that promotes RTI--an instructional model that links lessons, or "interventions," of increasing intensity with frequent monitoring of student progress--they are taking on the challenge of making RTI work for older students. RTI is a model of instruction promoted in the regulations that accompanied the 2004 reauthorization of the federal Individuals with Disabilities Education Act. It is often represented by three tiers, which include different levels of instruction by intensity. Progress monitoring, usually with short assessments, is used to determine whether a student is responding to the interventions, or lessons. This article discusses the RTI and describes how it has shown promise in secondary schools according to educators, although the framework is more commonly used with younger students.