This article describes intensive behavior intervention that is used with students who have behavioural difficulties. Joseph H. Wehby and Lee Kern report on 35 years of research in this area and note two conclusions: (1) Students with significant behavioral difficulties, including those with emotional disturbance (ED), have among the poorest social and academic outcomes of any group of students; and (2) Teachers and other school personnel feel inadequately prepared to work with these students. A probable contributing factor to these poor school outcomes is that educators often receive inadequate training on managing and supporting students with significant behavior issues. Wehby and Kern introduce "Intensifying Behavioral Interventions with an Adaptive Intervention Approach," an idea that has its roots in the tradition of good clinical practice and DBI. Teachers can easily use their experience and history with a student or use response patterns shown on typical school measures to modify a particular behavior intervention. The article provides an example that illustrates the process of adaptation and uses the most frequently reported Tier 2 intervention (involving small-group support programs that incorporate validated methods to help students develop self-control strategies or enhance social relationships in addition to improving academic performance), then describes the intensive and individualized Tier 3--functional assessment process, a problem-solving approach that relies on selecting relevant environmental factors for identifying the primary motivations for problem behavior and using that information as the centerpiece for developing an individualized behavior intervention plan. As teachers move forward toward improving the outcomes for this difficult-to-teach population, systematic adaptations of Tier 2 interventions and individualization of support within a multitiered system may furnish the best avenue for meaningful change.