Category:Companies based in Ontario

• Credit unions of Ontario‎ (2 C, 8 P)
• Crown corporations of Ontario‎ (5 C, 27 P)
• Defunct companies of Ontario‎ (1 C, 68 P)
• Manufacturing companies based in Ontario‎ (3 C, 21 P)
• Restaurants in Ontario‎ (3 C, 14 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, 16 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 (15 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, 102 P)

P

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

S

• Companies based in Sault Ste. Marie, Ontario‎ (5 P)
• Companies based in St. Catharines‎ (1 C, 6 P)

T

• Companies based in Thunder Bay‎ (13 P)
• Companies based in Toronto‎ (25 C, 493 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 (company)
• 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 Niagara Power
• 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
• 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