School boosters are tax-exempt organizations that engage in fundraising efforts to provide public schools with supplementary resources. This paper argues that prevailing forms of school boosting are defeasibly unjust. Section 1 shows that inequalities in public education funding in the United States violate John Rawls’s two principles of domestic justice. Section 2 argues that prevailing forms of school boosting exacerbate and plausibly perpetuate these injustices. Section 3 then contends that boosting thereby defeasibly violates Rawlsian principles of nonideal theory for rectifying injustice. Thus, boosting should be presumptively either made illegal or substantially reformed. Finally, Section 4 responds to potential objections.