Emotional and/or behavioral disorders (EBDs) are a group of disorders characterized by maladaptive behaviors that interfere with functioning. Disorders include attention deficit/hyperactivity disorder, oppositional defiant disorder, and conduct disorder. Students with an EBD are at risk for a number of negative long-term social, academic, occupational, and financial outcomes. This chapter summarizes intraindividual and environmental factors that affect the presentation of EBD, with an emphasis on oppositional defiant disorder and conduct disorder. It reviews methods for assessing EBD and how assessment can inform intervention. It then describes how students with EBD can be supported using a multitiered system of support in schools with examples of interventions at each tier. Educators play a key role in supporting students with EBD, but they need to develop effective skills to do so. They also benefit from the support of other allied professional and special education consultants.