Ontario is a province in east-central Canada.
Ontario may also refer ro:
Places
Belize
- Ontario, Belize, a village in Cayo District, Belize
Canada
- Ontario County, Ontario, the name of several historic counties
- Ontario (federal electoral district), a defunct federal electoral district
- Ontario (provincial electoral district), a defunct provincial electoral district
- Ecclesiastical Province of Ontario, an Anglican province
United States
- Ontario, California
- Ontario, Illinois
- Ontario, Indiana
- Ontario, Iowa
- Ontario, New York
- Ontario (CDP), New York
- Ontario County, New York
- Ontario, Ohio
- Ontario, Oregon
- Ontario, Wisconsin
- Ontario Township (disambiguation)
Lakes
- Lake Ontario, one of the Great Lakes on the boundary between the Canadian province of Ontario and the U.S. state of New York
- Ontario Lacus, a dark feature near the south pole of Saturn's moon Titan
Ships
- HMCS Ontario, several Canadian naval vessels
- HMS Ontario, several British naval vessels
- HMS Ontario (1780), British warship sunk during the American Revolution
- USS Ontario, several American naval vessels
Other uses
- Ontario (computer virus)
- Ontario (processor), a computer APU from AMD
- Ontario International Airport (ONT) in Ontario, California
- Ontario Motor Speedway, a 2.5-mile racetrack in Ontario, California
- 45554 Ontario, a British LMS Jubilee Class locomotive
- Ontario Bus Industries, the former name of Canadian bus manufacturer Orion Bus Industries