This study uses data from three longitudinal experimental evaluations of US state welfare reform programs to examine whether program-induced changes in families’ reliance on sibling care are linked with the effects of welfare programs on selected schooling outcomes of high risk, low-income adolescents. The findings from two of the welfare programs indicate that increased reliance on sibling care was concomitant with unfavorable effects of the programs on adolescent schooling outcomes. In the third welfare program examined, the program did not yield any increases in the use of sibling care or unfavorable effects on adolescent schooling outcomes, suggesting that sibling care is one likely contributor to the negative effects of welfare programs on adolescent schooling outcomes. These findings are discussed in terms of the pattern of the programs’ effects on families’ income, as well as maternal work on nonstandard schedules, aside from the programs’ effects on maternal employment, which play contributory roles in shaping the extent to which welfare programs led to less favorable effects on the schooling outcomes of adolescents with younger siblings.