Americans for Prosperity, founded in 2004, is a libertarian conservative political advocacy group in the United States funded by David Koch and Charles Koch. As the Koch brothers' primary political advocacy group, it is one of the most influential American conservative organizations.
After the 2009 inauguration of President Barack Obama, AFP helped transform the Tea Party movement into a political force. It organized significant opposition to Obama administration initiatives such as global warming regulation, the Patient Protection and Affordable Care Act, the expansion of Medicaid and economic stimulus. It helped turn back cap and trade, the major environmental proposal of Obama's first term. AFP advocated for limits on the collective bargaining rights of public-sector trade unions and for right-to-work laws, and it opposed raising the federal minimum wage. AFP played an active role in the achievement of the Republican majority in the House of Representatives in 2010 and in the Senate in 2014.
In the 2014 mid-term election cycle, AFP led all groups, other than political action committees, in spending on political television advertising. AFP's scope of operations has drawn comparisons to political parties. AFP, an educational social welfare organization, and the associated Americans for Prosperity Foundation, a public charity, are tax-exempt nonprofits. As a tax-exempt nonprofit, AFP is not legally required to disclose its donors to the general public. The extent of AFP's political activities while operating as a tax-exempt entity has raised concerns among some campaign finance watchdogs regarding the transparency of its funding.