A 501(c)(3) organization refers to corporations, trusts, unincorporated associations, or other types of organizations that are exempt from federal income tax under Section 501(c)(3) of Title 26 of the «United States Code». It is one of 29 types of 501(c) nonprofit organizations in the U.S.

The 501(c)(3) tax-exempt status applies to entities established and operated for public interests such as religious, educational, charitable, scientific, literary, testing for public safety, fostering national or international amateur sports competition, and preventing cruelty to children or animals.

The U.S. tax code allows donors to most 501(c)(3) organizations to deduct their charitable contributions from their federal income taxes. These deductions require documentation, such as a receipt for donations over $250. Because of this tax benefit, having 501(c)(3) status is crucial for the survival and operation of a charitable organization.

Many foundations and corporate charters stipulate that they will not donate to organizations without 501(c)(3) status. Similarly, individual donors might be deterred from contributing to such organizations due to the lack of tax deduction benefits.

Private foundations, sometimes called non-operating foundations, get most of their income from investments and donations. These funds are primarily donated to other organizations rather than being used directly for charitable activities. Private foundations are defined by Section 509(a) of the Internal Revenue Code as 501(c)(3) organizations that do not meet the criteria for public charity status.