Stephen Mather, American businessman and conservationist, co-founded the Thorkildsen-Mather Borax Company (born 1867)

Stephen Tyng Mather was an American industrialist and conservationist who was the first director of the National Park Service. As president and owner of Thorkildsen-Mather Borax Company he became a millionaire. Along with journalist Robert Sterling Yard, Mather led a publicity campaign known as the Mather Mountain Party to promote the creation of a unified federal agency to oversee National Parks administration, which was established in 1916. In 1917, Mather was appointed to lead the NPS, the new agency created within the Department of the Interior. He served until 1929, during which time Mather created a professional civil service organization, increased the numbers of parks and national monuments, and established systematic criteria for adding new properties to the federal system.

Thorkildsen-Mather Borax Company was a borax mining company founded in 1898 by Stephen Mather and Thomas Thorkildsen. The two men were both employees of Francis Marion "Borax" Smith's Pacific Coast Borax Company, but they left the company to form this new company and went into direct competition with their former boss. The company was later renamed Sterling Borax. Francis Marion Smith subsequently bought out their company in 1911.