The purpose of this manuscript is to conceptualize a unified Response to Intervention (RTI) model that may be applied to Head Starts or preschools with typical children and those identified as "at risk," or "children with disabilities." RTI basically provides a specific and discrete cumulative intervention history of services which also may be used as evaluation data. Intervention sequences may include universal and classwide (Tier 1), embedded and small group (Tier 2), and individualized interventions (Tier 3) on a continuum defined by intervention intensity. Advantages, challenges, limitations, criticism, and opportunities for RTI consultation and support are discussed.