The underlying premise of Response to Intervention (RTI) is that schools should not wait until students fall far enough behind to qualify for special education to provide them with the help they need. Instead, schools should provide targeted and systematic interventions to all students as soon as students demonstrate the need. However, schools that focus primarily on raising test scores, implement RTI as a series of discrete actions rather than an on-going process, implement RTI mostly to comply with the law, or see student failure as a failure in learning will struggle to reap the benefits of RTI. When all students have guaranteed access to rigorous curriculum and effective initial teaching, targeted and timely supplemental support, and personalized intensive support provided by highly trained educators, few will experience failure. This article addresses how to use differentiated instruction and assessment to close the achievement gap.