A meta-analysis was conducted to examine gender differences in the effects of early childhood education programs on children's cognitive, academic, behavioral, and adult outcomes. Significant and roughly equal impacts for boys and girls on cognitive and achievement measures were found, although there were no significant effects for either gender on child behavior and adult outcomes such as employment and educational attainment. Boys benefited significantly more from these programs than girls on other school outcomes such as grade retention and special education classification. We also examined important indicators of program quality that could be associated with differential effects by gender.