State virtual schools are among the fastest growing programs in K–12 public education. Twenty-eight states now have virtual school programs that enroll students statewide, up from four such programs in 1997. Last year, some 139,000 students enrolled in at least one course through a state virtual school. Two of the oldest and largest state on-line programs, in Utah and Florida, have both expanded by more than 50 percent over the past five years. If trends continue—if states continue to create virtual schools and recently created programs grow at even half the rate of the programs in Florida and Utah—we can expect a half-million students to enroll in state virtual schools in just a few years.