Mathematics proficiency is a gateway to accessing positive in-school and postschool outcomes. Schools must address student responsiveness to instruction and intervene with effective instructional practices to ensure students acquire necessary knowledge and skills to use mathematics to achieve desirable outcomes. Data suggest many students with emotional or behavioral disorders are not reaching mathematics proficiency criteria, which in turn indicates instructional failure is occurring. The focus of this chapter is identifying core characteristics of mathematics instruction and intervention to support student learning of mathematics—with a specific focus on how instruction can be intensified for students with emotional or behavioral disorders.