A non-profit organization is a group organized for purposes other than generating profit and in which no part of the organization's income is distributed to its members, directors, or officers. Non-profit corporations are often termed "non-stock corporations." They can take the form of a corporation, an individual enterprise (for example, individual charitable contributions), unincorporated association, partnership, foundation (distinguished by its endowment by a founder, it takes the form of a trusteeship), or condominium (joint ownership of common areas by owners of adjacent individual units incorporated under state condominium acts). Non-profit organizations must be designated as nonprofit when created and may only pursue purposes permitted by statutes for non-profit organizations. Non-profit organizations include churches, public schools, public charities, public clinics and hospitals, political organizations, legal aid societies, volunteer services organizations, labor unions, professional associations, research institutes, museums, and some governmental agencies.

Non-profit entities are organized under state law. For Non-profit corporations, some states have adopted the Revised Model Non-Profit Corporation Act (1986). For Non-profit associations, a few states have adopted the Uniform Unincorporated Non-Profit Association Act. Some states exempt non-profit organizations from state tax and state employment programs such as unemployment compensation contribution. Some states give non-profit organizations immunity from tort liability and other states limit tort liability by enacting a damage cap. State law also governs solicitation privileges and accreditations requirements such as licenses and permits. Each state defines non-profit differently. Some states make distinctions between organizations not operated for profit without charitable goals (like a sports or professional association) and charitable associations in order to determine what legal privileges the respective organizations will be given.

For federal tax purposes, an organization is exempt from taxation if it is organized and operated exclusively for religious, charitable, scientific, public safety, literary, educational, prevention of cruelty to children or animals, and/or to develop national or international sports. Social security tax is also currently optional although 80 percent of the organizations elect to participate.