School choice is growing, due to growth of charter schools, private voucher programs, and No Child Left Behind requirements that school districts offer options to children in low-performing schools. Growth can bring dangers if choice is implemented carelessly. Recent research on choice shows that program design and implementation matter: the quality of parent information, the amounts of money that follow children to schools of choice, and rules governing school admissions all help determine whether disadvantaged children benefit from choice. Smart program design can also reduce the risk of harm to children left behind in regular public schools. The article describes a needed research program on doing choice right, which can provide guidance to local leaders charged with choice implementation.