Jean-Sébastien Lamoureux (born February 28, 1974) is a Canadian lawyer, manager and former politician in the province of Quebec. He served in the National Assembly of Quebec as a Liberal from 1998 until his resignation in 2001.
Lamoureux was born in Anjou on the east end of the Island of Montreal. He worked as an intern in the office of the Canadian minister of Foreign Affairs from 1994 to 1995 and in the office of the leader of the official opposition of Quebec in 1996. Lamoureux received a law degree from the Université de Montréal in 1996, was called to the bar of Quebec the following year, and worked with the firm Leduc, Leblanc from 1997 to 1998. In 2001, he received a graduate degree in management from HEC Montréal.
His father, Jacques Lamoureux, has served as president of the Quebec Liberal Party.
Lamoureux was nominated as the Liberal candidate for Anjou in the buildup to the 1998 provincial election. The governing Parti Québécois (PQ) had won the seat by a narrow margin in the previous election, and the contest was expected to be close. Lamoureux focused his campaign on opposition to another referendum on Quebec sovereignty, in the aftermath of the Canadian federalist option's narrow victory in 1995. On election day, he defeated incumbent PQ cabinet minister Pierre Bélanger by only 143 votes.