Mark Adam Foley (born September 8, 1954) is an American former politician who served as a member of the United States House of Representatives. He served from 1995 until 2006, representing the 16th District of Florida as a member of the Republican Party, before resigning due to revelations that he had sent sexually explicit messages to teenaged boys who had served as congressional pages in what came to be known as the Mark Foley scandal.

Foley resigned from Congress on September 29, 2006, acting on a request by the Republican leadership after allegations surfaced that he had sent suggestive emails, as well as sexually explicit instant messages, to teenage boys who had formerly served and were at that time serving as Congressional pages. As a result of the disclosures, the Federal Bureau of Investigation (FBI) and the Florida Department of Law Enforcement conducted investigations of the messages to find possible criminal charges. Each ended with no criminal finding. In the case of the Florida Department of Law Enforcement, FDLE commissioner Gerald Bailey with the closure of the case stated that the "FDLE conducted as thorough and comprehensive investigation as possible considering Congress and Mr. Foley denied us access to critical data." The House Ethics Committee also conducted an investigation into the response of the House Republican leadership and their staff to possible earlier warnings of Foley's conduct.

Foley was born in Newton, Massachusetts, the son of Frances and Edward Joseph Foley Jr., a teacher and civic activist. Foley served in the Florida House of Representatives 1990–1992 and then in the Florida State Senate 1993–1994.

Foley was elected to the U.S. House in 1994 with 58 percent of the vote, defeating Democrat John Comerford. He was re-elected in 1996 with 64 percent of the vote against Democrat Jim Stuber and again in 1998 (this time without opposition). He was re-elected in 2000 with 60 percent of the vote against Democrat Jean Elliott Brown and Reform Party candidate John McGuire. Constitution Party candidate Jack McLain was his only opponent in 2002. He was re-elected in 2002 with 79 percent of the vote and in 2004 with 68 percent of the vote.

Foley was a moderate Republican. He spent most of his tenure in Congress as a member of the powerful House Ways and Means Committee. He was also the first public figure to imply that Vice President Al Gore claimed to have invented the Internet. On March 12, 1999, Reuters reported Foley as saying, "The Vice President is mistaken. The only thing he has ever invented is another tax. He did not invent the Internet but he sure did tax it."

In late 2000, Foley played a large role in aiding George W. Bush during the Presidential election recount controversy in Florida.

In 2006, Foley was a member of the Republican House leadership, serving as deputy whip.

In 2003, Foley was widely considered the Republican front-runner for Bob Graham's Senate seat, especially after Graham had announced his retirement. However, longstanding rumors surfaced that Foley was either homosexual or bisexual and was in a long-term homosexual relationship. The story was initially published only in local and gay press; then the New Times broke the story in the mainstream press. Other alternative press rivals, including the New York Press, then addressed the topic. Foley held a press conference to denounce the "revolting" rumors and stated that his sexual orientation was unimportant, but did not specifically deny the rumors. A few weeks later, he withdrew his candidacy, saying his father's battle with cancer had caused him to reassess his perspective on life (the seat was later won by Republican Mel Martinez). Foley had raised $3 million in campaign contributions before withdrawing.