Americans for Prosperity Foundation v. Bonta, 141 S.Ct. 2373 (2021) is a significant United States Supreme Court case focused on the issue of donor disclosure for non-profit organizations. The case arose when the Americans for Prosperity Foundation challenged California's mandate requiring non-profits to disclose the identities of their major donors to the state's Attorney General as a condition for soliciting contributions within the state. This requirement was aimed at promoting transparency and accountability in charitable fundraising but raised concerns about privacy and the potential chilling effect on free speech.

The Supreme Court consolidated this case with another related case, Thomas More Law Center v. Bonta, highlighting the broader implications of donor disclosure laws on First Amendment rights. In a pivotal ruling issued in July 2021, the Court determined, in a 6–3 decision, that California's disclosure requirement imposed an unconstitutional burden on donors’ First Amendment rights. The majority opinion argued that the law was not narrowly tailored to serve the state’s interests in transparency and accountability, rendering it constitutionally invalid.

This ruling underscored the Court's commitment to protecting free speech and privacy, particularly in the context of political and charitable activities. The decision has far-reaching implications for non-profit organizations, potentially encouraging greater anonymity for donors and limiting states' abilities to impose similar disclosure requirements in the future. The case reflects a broader debate about the balance between transparency in political donations and the right to free expression, highlighting ongoing tensions in the regulation of political speech and fundraising in the United States.