John Jenkins, American-Australian businessman and politician, 22nd Premier of South Australia (died 1923)

John Greeley Jenkins was an American-Australian politician. He was Premier of South Australia from 1901 to 1905. He had previously served as Minister for Education and the Northern Territory and Commissioner for Public Works under Thomas Playford II, Commissioner of Public Works under Charles Kingston and Chief Secretary under Frederick Holder. He was subsequently Agent-General for South Australia from 1905 to 1908.

The Premier of South Australia is the head of government in the Australian state of South Australia. The Government of South Australia follows the Westminster system, with the Parliament of South Australia acting as the legislature. The Premier is appointed by the Governor of South Australia, and by modern convention holds office by virtue of their ability to command the support of a majority of members of the lower house of Parliament, the House of Assembly.