In this study, students and their teachers participated in a layered approach to reading intervention in kindergarten through third grade that included professional development for teachers in scientifically based reading instruction, ongoing measurement of reading progress, and additional small-group or individual instruction for students whose progress was insufficient to maintain grade-level reading achievement. Reading outcomes were compared with historical control groups of students in the same schools. The findings revealed overall improvements in reading, improved reading for students who began the study in high-risk categories, and decreases in the incidence of reading disability at the end of third grade. Implications for scaling up are discussed.