Fee simple is an ownership interest in real property that is the most full, unlimited, and absolute property interest recognized by law. This ownership interest of title in fee simple is also referred to as fee simple absolute; estate in fee simple; fee simple title; or simply fee, and the term is usually used to indicate the real property ownership interest a seller is transferring to a buyer.

The rights of a fee simple property owner are limited by the government’s power to tax the land (property taxes) and to purchase the land through the compulsory process mandated by state law—often as provided in the state’s constitution or in the state’s statutes—which is known as eminent domain.

In limited circumstances fee simple ownership may also be subject to the state’s police powers, the law of escheat (when the property owner dies without a will and without heirs), and encumbrances or deed restrictions on the use of the land.

In Hawaii, fee simple ownership represents the most complete form of ownership in real estate, granting the holder full rights to use, enjoy, and dispose of the property without any time limitations, subject to certain legal restrictions. The owner of a fee simple title has the right to sell the property, lease it, pass it on to heirs, and use it in any lawful manner. However, these rights are subject to the government's power to tax the property, and the property may be taken by the government for public use through eminent domain, in accordance with the Hawaii Revised Statutes and applicable constitutional provisions. Additionally, the state's police powers may impose regulations on the use of the property for the protection of public health, safety, morals, and general welfare. If a property owner dies intestate (without a will) and without heirs, the property may escheat, or revert, to the state. Lastly, fee simple ownership can be limited by encumbrances or deed restrictions, which may regulate how the property can be used or developed.