The Antiquities Act of 1906 is an act passed by the United States Congress and signed into law by Theodore Roosevelt giving the President of the United States authority to place certain lands under control of the federal government by executive order, bypassing Congressional oversight. The Act has been used over a hundred times since its passage. Its use frequently creates significant controversy.

The Antiquities Act was intended to allow the President to set aside certain valuable public natural areas as park and conservation land. These areas are given the title of U.S. National Monument. It also allows him to reserve or accept private lands for that purpose. The aim is to protect all historic and prehistoric sites on United States federal lands and to prohibit excavation or destruction of these antiquities. With this act, this can be done much more quickly than going though the Congressional process of creating a national park. The Act states that areas of the monuments are to be confined to the smallest area compatible with the proper care and management of the objects to be protected.

For any excavation, the Act requires that a permit (Antiquities Permit) be obtained from the Secretary of the department which has jurisdiction over those lands.