Abstract In 1981, Chile introduced nationwide school choice by providing vouchers to any student wishing to attend private school. As a result, more than 1000 private schools entered the market, and the private enrollment rate increased by 20 percentage points, with greater impacts in larger, more urban, and wealthier communities. We use this differential impact to measure the effects of unrestricted choice on educational outcomes. Using panel data for about 150 municipalities, we find no evidence that choice improved average educational outcomes as measured by test scores, repetition rates, and years of schooling. However, we find evidence that the voucher program led to increased sorting, as the “best” public school students left for the private sector.