The 2012 United States Senate election in Maine was held on November 6, 2012, alongside a presidential election, other elections to the United States Senate in other states, as well as elections to the United States House of Representatives and various state and local elections. Despite initially declaring her candidacy and being considered the favorite, popular incumbent Republican U.S. Senator Olympia Snowe unexpectedly decided to retire instead of running for reelection to a fourth term.

Olympia Jean Snowe is an American businesswoman and politician who was a United States Senator from Maine from 1995 to 2013. Snowe, a member of the Republican Party, became known for her ability to influence the outcome of close votes, including whether to end filibusters. In 2006, she was named one of America's Best Senators by Time magazine. Throughout her Senate career, she was considered one of the most moderate members of the chamber.