Algonquin or Algonquian—and the variation Algonki(a)n—may refer to:
- Algonquian languages, a large subfamily of Native American languages in a wide swath of eastern North America from Canada to Virginia
- Algonquin language, the language of the Algonquin people in Canada, for which the Algonquian languages group is named
- Algonquian peoples, Indigenous tribes of North America composed of people who speak the Algonquian languages
- Algonquin people, a subgroup of Algonquian people who speak the Algonquin language and live in Quebec and Ontario, Canada
- The Algonquin, a hotel in St. Andrews, New Brunswick
- Algonquin Club, Boston, Massachusetts
- Algonquin Hotel, New York City
- Algonquin Round Table, a group of New York writers, critics, actors and wits who regularly congregated at the Algonquin Hotel
- Algonquin Power & Utilities, a utility company operating in North America
- Algonquin Radio Observatory, a radio telescope research facility in the Algonquin Provincial Park, Ontario, Canada
- Algonquin Regional High School, located in Northborough, Massachusetts
- Algonquin College, a college in Ontario, Canada
United States
- Algonquin, Illinois
- Algonquin Township, McHenry County, Illinois
- Algonquin, Louisville, Kentucky
- Algonquin, Maryland
- Algonquin, Michigan
- Algonkian Regional Park, Virginia
- Algonquin Peak, the second highest mountain in New York state
- "Algonquin", A 12,574' peak in the Indian Peaks Wilderness, Colorado
- "Algonquin", also a small Northwestern community located in the city limits of Sault Ste. Marie, Michigan