The Action démocratique du Québec ("Democratic Action of Quebec"), commonly referred to as the ADQ, was a right-wing populist and conservative provincial political party in Quebec, Canada. On the sovereignty question, it defined itself as autonomist; it had support from nationalists and federalists. Its members were referred to as adéquistes, a name derived from the French pronunciation of the initials 'ADQ'.

The party was founded by dissidents of the Quebec Liberal Party who did not accept the Charlottetown Accord, and first contested the 1994 provincial election, electing Mario Dumont to the National Assembly. Under longtime leader Dumont, the ADQ had a strong showing in the 2007 provincial election, reducing the ruling Quebec Liberal Party (PLQ) to a minority government and relegating the Parti Québécois (PQ) to third place. The ADQ won 41 seats with 31% of the popular vote to serve as the Official Opposition in the National Assembly. However, the ADQ's popularity declined significantly soon afterward and in the 2008 provincial elections, the party failed to secure at least twenty percent of the popular vote or twelve Members of the National Assembly (MNAs) in the last election, and consequently lost official party status, though in early 2009 it was recognised as an official party by the PLQ and the PQ.

On 21 January 2012, the membership approved a merger with the Coalition Avenir Québec. The merger was recognised by the Directeur général des élections du Québec on 14 February 2012.