Gilles Duceppe (b. July 22, 1947) is a social democratic politician in the Province of Quebec, Canada. He is a Member of Parliament and the leader of the sovereigntist Bloc Québécois also known as the (Bloc). He is the son of a well-known Québécois actor, Jean Duceppe, and Hélène Rowley.

Duceppe is a native of Montreal, Quebec. He studied political science at the University of Montreal. In his youth, he advocated communism, and was a card-carrying member of the Communist Worker's Party. Duceppe later said his three-year membership in the Communist Worker's Party was a mistake brought on by a search for fundamental change [1]. He later became a trade union negotiator.

In 1990, Duceppe was elected to the Canadian House of Commons for the newly-formed Bloc Québécois in a by-election in Montreal's Laurier—Sainte-Marie riding. At the time, he was forced to run as an independent because the Bloc had not been registered by Elections Canada as a political party. All of the Bloc's other Members of Parliament had crossed the floor from either the Progressive Conservative Party or the Liberal Party earlier that year. Duceppe's victory in a by-election demonstrated, for the first time, that the party had electoral support in Quebec and was capable of winning elections. Previously, many pundits (and members of other parties) predicted that the Bloc would not be able to gain the support of the voters.

In 1996, when Lucien Bouchard stepped down as Bloc leader to become leader of the Parti Québécois, Duceppe served as interim leader of the party until Michel Gauthier was elected later that year. However, Gauthier was forced out of the party leadership in 1997, and Duceppe became party leader and Leader of the Opposition.

In the 1997 general election, the Bloc lost official opposition status, slipping to third place in the House of Commons behind the Reform Party. The party's caucus in the Commons was reduced went from 54 to 44 seats, and fell further to 38 seats in the 2000 election. Duceppe was criticized for his ineffective campaign skills in both elections, but no serious challenge to his leadership was mounted.

However, with the sponsorship scandal that erupted soon after Jean Chrétien's departure as Liberal leader in 2003, the Bloc's fortunes improved markedly. In the 2004 election, Duceppe's Bloc won 54 seats in the Commons, returning to the party's all-time high. During the election's national debates, Duceppe's lucid explanations and chastising of the other national party leaders lead to him being judged to be the best speaker by both the French and English media. The unification of the Progressive Conservative and Canadian Alliance parties meant that the Bloc did not form the Opposition as it did when it last had as many seats.

With Chrétien's departure, Duceppe became the longest-serving current leader of a major party in Canada.

With recent success of the Bloc and his increasingly well-received performance as leader, speculation has grown that Duceppe might seek the leadership of the Parti Québécois.