The Every Student Succeeds Act (ESSA) requires states to identify and turn around struggling schools, with federal school improvement money required to fund evidence-based policies. Most research on turnarounds has focused on individual schools, whereas studies of district-wide turnarounds have come from relatively exceptional settings and interventions. We study a district-wide turnaround of a type that may become more common under ESSA, an accountability-driven state takeover of Massachusetts's Lawrence Public Schools (LPS). A differences-in-differences framework comparing LPS to demographically similar districts not subject to state takeover shows that the turnaround's first 2 years produced sizable achievement gains in math and modest gains in reading. We also find no evidence that the turnaround resulted in slippage on nontest score outcomes and suggestive evidence of positive effects on grade progression among high school students. Intensive small-group instruction over vacation breaks may have led to particularly large achievement gains for participating students.