The National Association of State Directors of Special Education (NASDSE, 2005) defines response to intervention (RTI) as the practice of providing high-quality instruction and intervention based on a student's needs, changing instruction and/or goals through frequent monitoring of progress, and applying the student response data to important educational decisions. Although there is no universally accepted RTI model or approach, it is typically understood within the context of multiple tiers of intervention service delivery for students with difficulties. In other words, students who are identified as at-risk through universal screening have their progress monitored and receive increasingly intense, multi-tiered interventions, which may evaluate in eligibility for special education and related services. RTI models currently in practice may vary across local education agencies (LEAs) and states. However, they use a generally similar structure with some common components. According to NASDSE (2005), three essential components of RTI are as follows: (1) Multi-tiered intervention service delivery; (2) Integrated data collection/assessment system; and (3) Data-based decisions based on a problem-solving model. Prior to implementation, strategic planning and staff development will be needed to address the above components. It is also important to recognize that the successful implementation of RTI hinges upon such prerequisite elements as building capacity and parent involvement. To fully incorporate RTI, school districts must assess their readiness and capacity to adopt and implement RTI practices for all academic areas and classroom management. School districts then develop a plan for implementing RTI that should include building capacity. An RTI plan is expected to take several years to fully implement, thus districts and schools are encouraged to start small before moving to a district-wide approach. This is due to the considerable amount of professional development that needs to be provided in the beginning stages of establishing RTI systems to build capacity. It will be equally important for all staff to receive on-going professional development support after an RTI system has been put into place. A glossary is included.