Reading Recovery is an example of a widely used early literacy intervention for struggling first-grade readers, with a research base demonstrating evidence of impact. With funding from the U.S. Department of Education's i3 program, researchers conducted a 4-year evaluation of the national scale-up of Reading Recovery. The evaluation included an implementation study and a multisite randomized controlled trial with 6,888 participating students in 1,222 schools. The goal of this study was to understand whether the impacts identified in prior rigorous studies of Reading Recovery could be replicated in the context of a national scale-up. The findings of this study reaffirm prior evidence of Reading Recovery's immediate impacts on student literacy and support the feasibility of successfully scaling up an effective intervention.