Category:Companies based in Ontario

• Credit unions of Ontario (2 C, 8 P)
• Crown corporations of Ontario (8 C, 29 P)
• Defunct companies of Ontario (2 C, 69 P)
• Manufacturing companies based in Ontario (3 C, 21 P)
• Restaurants in Ontario (3 C, 15 P)

B

• Companies based in Barrie (6 P)
• Companies based in Brampton (1 C, 19 P)
• Companies based in Burlington, Ontario (7 P)

E

• Electric power companies of Ontario (2 C, 15 P)
• Energy companies of Ontario (1 C, 5 P)
• Entertainment companies based in Ontario (2 P)

F

• Financial services companies based in Ontario (1 C)

G

• Companies based in Greater Sudbury (14 P)
• Companies based in Guelph (12 P)

H

• Companies based in Hamilton, Ontario (24 P)

K

• Companies based in Kingston, Ontario (10 P)

L

• Companies based in London, Ontario (46 P)

N

• Companies based in North Bay, Ontario (8 P)

O

• Companies based in Oakville, Ontario (15 P)
• Ontario railways (5 C, 30 P)
• Companies based in Oshawa (11 P)
• Companies based in Ottawa (4 C, 103 P)

P

• Companies based in the Regional Municipality of Peel (3 C)

S

• Companies based in Sault Ste. Marie, Ontario (6 P)
• Companies based in St. Catharines (1 C, 6 P)

T

• Companies based in Thunder Bay (13 P)
• Companies based in Toronto (25 C, 470 P)

V

• Vandestadt and McGruer Limited (1 C, 1 P)

W

• Companies based in the Regional Municipality of Waterloo (3 C, 6 P)
• Companies based in Windsor, Ontario (8 P)

Y

• Companies based in the Regional Municipality of York (5 C, 1 P)

A

• Algoma Power
• Algoma Tankers Limited
• Angels of Flight Canada
• Aphria Inc.
• Arrangement Finders
• Arva Industries

B

• BionX
• Black Diamond Cheese
• Black Walk
• Blue Mountain Pottery
• BPC Generation Infrastructure Trust
• BrandAID Project
• Brandon Gray Internet Services
• Bruce Power

C

• Canadian Elite Basketball League
• Canadian Tire Financial Services
• Chudleigh's Limited
• Coach Canada
• Cobourg Car Works
• Collingwood Shipbuilding
• Condrain
• Creemore Springs

D

• Digital Bolex
• Ditchburn Boats
• Duke Boats
• Durham Region Transit

E

• ECampusOntario
• Electra Battery Materials
• Electrify Canada
• Element Yachts
• Execulink Telecom

F

• Fifth Wheel Truck Stops
• Fitzhenry & Whiteside
• Fleet Canada
• Fun Guyz

G

• Gentec International
• Geotab
• Great Lakes Airlines (Canada)
• GreenMantra Technologies
• Gunther Mele

H

• Haley Industries

I

• IES Ltd
• Ingersoll Axles
• Iroquois Cranberry Growers

J

• Joco Communications
• John Speight and Sons

K

• Kawartha Dairy Company

L

• LabX Media Group
• Larche Communications
• Look Communications
• LW Stores

M

• MEI Academy
• Metal Supermarkets
• My Broadcasting Corporation

N

• NAD Electronics
• Naden Boats
• Nations Fresh Foods

O

• Objectworld Communications
• Omar Gandhi
• ONroute
• Optelian
• OPTrust
• Owen Sound Transportation Company

P

• Playdium
• PSB Speakers

R

• R.M. Bélanger Ltd.
• RAFM Company
• Red Deer Press
• Robbinex
• Ross Video

S

• Sam Bat
• Samuel, Son & Co.
• Sheridan Nurseries
• Smoke's Poutinerie
• Sparling's Propane
• Spool (record label)
• Steelback Brewery

T

• Teeswater Creamery
• TekSavvy
• Trillium Railway

U

• Union Gas

W

• Waste Connections
• Whiteoaks Communications Group

Y

• Yorkville Sound

Z

• Zenair