AARP, formerly the American Association of Retired Persons, is an interest group in the United States focusing on issues affecting those 50 and older. The organization, which is headquartered in Washington, D.C., said it had more than 38 million members as of 2018. The magazine and bulletin it sends to its members are the two largest-circulation publications in the United States.

AARP was formed in 1958 by Ethel Percy Andrus, a retired educator from California, and Leonard Davis, who later founded Colonial Penn's insurance companies. It is an influential lobbying group in the United States. AARP sells paid memberships, and markets insurance and other services to its members.

AARP is a nonpartisan 501(c)(4) nonprofit that advocates for older Americans on a number of federal health and fiscal issues such as Medicare and Social Security, and at the state and local level for better community healthcare services and lower utility rates. It fights age discrimination in the workforce, lobbies for lower prescription drug prices, and educates seniors about consumer fraud through the AARP Fraud Watch Network.

AARP has millions of volunteer activists and offices in every state, as well as Washington D.C., Puerto Rico, and the Virgin Islands.

Through affiliated organizations such as the AARP Foundation, AARP helps seniors with legal assistance, tax preparation, job training, and personal finance.

Members receive AARP Magazine and the AARP Bulletin, the top-circulating consumer publications in the country, along with special offers and discounts related to travel, restaurants, prescriptions, and more. A full AARP membership is available to those 50 and older; however, those under 50 can also join.

AARP licenses its brand to certain products, including Medicare insurance with UnitedHealthcare. A volunteer board of directors oversees the organization.

According to its 2018 Consolidated Financial Statement, the largest sources of income were: