Albert Arnold Gore Jr. (born March 31, 1948) is an American politician, businessman, and environmentalist who served as the 45th vice president of the United States from 1993 to 2001 under President Bill Clinton. Gore was the Democratic nominee for the 2000 presidential election, losing to George W. Bush in a very close race after a Florida recount.

The son of politician Albert Gore Sr., Gore was an elected official for 24 years. He was a U.S. representative from Tennessee (1977–1985) and from 1985 to 1993 served as a U.S. senator from that state. He served as vice president during the Clinton administration from 1993 to 2001, defeating incumbents George H. W. Bush and Dan Quayle in 1992, and Bob Dole and Jack Kemp in 1996. The 2000 presidential election was one of the closest presidential races in history. Gore and his running mate Joe Lieberman won the popular vote, but after a controversial election dispute over a Florida recount (settled by the U.S. Supreme Court, which ruled 5–4 in favor of Bush), he lost the election to Republican opponent George W. Bush in the Electoral College. As of 2023, Gore’s 1990 re-election remains the last time Democrats won a Senate election in Tennessee.

After his term as vice-president ended in 2001, Gore remained prominent as an author and environmental activist, whose work in climate change activism earned him (jointly with the IPCC) the Nobel Peace Prize in 2007. Gore is the founder and current chair of The Climate Reality Project, the co-founder and chair of Generation Investment Management, the now-defunct Current TV network, a member of the Board of Directors of Apple Inc. and a senior adviser to Google. Gore is also a partner in the venture capital firm Kleiner Perkins, heading its climate change solutions group. He has served as a visiting professor at Middle Tennessee State University, Columbia University Graduate School of Journalism, Fisk University and the University of California, Los Angeles. He served on the Board of Directors of World Resources Institute.

Gore has received a number of awards that include the Nobel Peace Prize (joint award with the Intergovernmental Panel on Climate Change, 2007), a Grammy Award for Best Spoken Word Album (2009) for his book An Inconvenient Truth, a Primetime Emmy Award for Current TV (2007), and a Webby Award (2005). Gore was also the subject of the Academy Award winning (2007) documentary An Inconvenient Truth in 2006, as well as its 2017 sequel An Inconvenient Sequel: Truth to Power. In 2007, he was named a runner-up for Time's 2007 Person of the Year. In 2008, Gore won the Dan David Prize for Social Responsibility.