Students with emotional and behavioral difficulties are often unserved or underserved by schools and by mental health systems. One reason for the under identification of these students is the current and past definitions of emotional disturbance (ED) specified in federal special education legislation (IDEA and IDEIA). These definitions are vague, illogical, and self-contradictory, leading to the wide variability among states in prevalence rates of this disability. The author proposes an alternative approach to defining ED based on response to intervention (RTI). RTI provides the basis for changing, intensifying, and withdrawing interventions for students' emotional and behavioral difficulties. He describes advantages and best practices in using RTI, and provides a discussion of early identification and screening procedures for students who are at risk for ED. (Contains 1 table.)