In the United States, enrollments in preschool center-based programs have leveled off at about 75 percent of four-year-olds and 50 percent of three year olds. Nearly all government programs restrict eligibility to children in low-income families, and these families have substantially increased preschool participation rates as a result. However, in the last decade little progress was made toward increasing enrollments, despite increases in government spending, and less than half of children in poverty attend public programs even at age four. The average educational quality of private programs is quite low, and public programs are only modestly better. As a result, the educational effectiveness of preschool programs in the United States tends to be much weaker than that of the well-known programs research has shown be cost-effective. This paper considers whether publicly funded preschool education for all children would alleviate these problems. Universal public preschool education would reach many more children in poor and low-income families. For means-tested programs constantly changing incomes present a moving target, while the stigma associated with programs for the poor also limits participation. Program effectiveness would be at least as good in a universal program as in targeted program, and effectiveness might actually improve. One source of increased effectiveness is peer effects on learning. In addition, parents from higher-income families may be better advocates for quality, and political support for quality may be higher. Children from middle- and higher-income families also will benefit from high-quality publicly-subsidized preschool programs. A universal approach will cost more than current targeted programs, but moving from targeted to universal public preschool education is likely to produce benefits that far exceed the additional cost.