The Citadelle — the French name is used both in English and French^{[citation needed]} — is a military installation and official residence located atop Cap Diamant, adjoining the Plains of Abraham in Quebec City, Quebec, Canada. This citadel is part of the fortifications of Quebec City.

The Citadelle is a National Historic Site of Canada, and also forms part of the Fortifications of Quebec National Historic Site of Canada. The fortress is located within the "Historic District of Old Quebec", which was designated a World Heritage Site in 1985.