HMCS Calgary is a Halifax-class frigate that has served in the Canadian Forces and Royal Canadian Navy since 1995. Calgary is the sixth vessel in her class and the second vessel to carry the name Calgary. She was built as part of the Canadian Patrol Frigate Project. Calgary began the FELEX refit in June 2012. She is assigned to Maritime Forces Pacific (MARPAC) and is homeported at CFB Esquimalt. Calgary serves on MARPAC missions protecting Canada's sovereignty in the Pacific Ocean and enforcing Canadian laws in its territorial sea and exclusive economic zone.

The Halifax-class frigate, also referred to as the City class, is a class of multi-role patrol frigates that have served the Royal Canadian Navy since 1992. The class is the outcome of the Canadian Patrol Frigate Project, which dates to the mid-1970s. HMCS Halifax was the first of an eventual twelve Canadian-designed and Canadian-built vessels which combine traditional anti-submarine capabilities with systems to deal with surface and air threats as well. Ships of the class are named after capital cities of Canadian provinces, the capital of Canada, Ottawa, and the major cities of Calgary, Montreal, and Vancouver.