Stephen Tyng Mather (July 4, 1867 – January 22, 1930) was an American industrialist and conservationist who as president and owner of Thorkildsen-Mather Borax Company became a millionaire. With his friend and journalist Robert Sterling Yard, Mather led a publicity campaign to promote the creation of a unified federal agency to oversee National Parks administration, which was established in 1916.