Aleksander Kwaśniewski (Polish pronunciation: [alɛˈksandɛr kfaɕˈɲɛfskʲi] (listen); born 15 November 1954) is a Polish politician and journalist. He served as the President of Poland from 1995 to 2005. He was born in Białogard, and during communist rule, he was active in the Socialist Union of Polish Students and was the Minister for Sport in the Communist government during the 1980s. After the fall of Communism, he became a leader of the left-wing Social Democracy of the Republic of Poland, a successor to the former ruling Polish United Workers' Party, and a co-founder of the Democratic Left Alliance.

Kwaśniewski was elected to the presidency in 1995, defeating the incumbent, Lech Wałęsa. He was re-elected to a second and final term as president in 2000 in a decisive first-round victory. Although he was praised for attempting to further integrate Poland into the European Union, he faced criticism for involving the country in the Iraq War. His term ended on 23 December 2005, when he handed over power to his elected successor, conservative Lech Kaczyński.