Marshall Clement "Mark" Sanford Jr. (born May 28, 1960) is a United States politician from South Carolina, currently serving as the Governor of South Carolina. From 1995 to 2001, he served as the Republican representative in the United States House of Representatives for South Carolina's 1st congressional district, and was a staunch conservative.

In 2002, he was elected the 115th Governor of South Carolina, defeating Democratic incumbent Jim Hodges, and reelected in 2006. As governor, he has a contentious relationship with the South Carolina legislature: notably, he made public statements that he would reject stimulus funds for his state from the American Recovery and Reinvestment Act of 2009. Following a subsequent battle in the South Carolina Supreme Court, he was forced to accept the funds.

On June 24, 2009, Sanford resigned as chairman of the Republican Governors Association, after he publicly revealed that he had had an affair with an Argentine woman, María Belén Chapur. Sanford has since been criticized for his external affairs and use of taxpayer-funded planes to fly to Argentina, while previously insisting that he went hiking on the Appalachian Trail during his five-day absence.

Sanford is also a real estate developer and Air Force Reserve captain.