Canada's National Parks are very lovely places to camp. Some are very accessible; others are not easily reached except by plane or boat. Some of the more popular parks have a reservations system in place, as well as first-come, first-serve campgrounds. Like in the US, if you can't get a reservation, it might be a good idea to camp outside of the national park, and go in early (i.e. before 9 am) to secure a spot.
Not all national parks have campgrounds. Though a link will be available for all parks that have them, it will be noted if there is no campground within that park.
National Parks in Canada are generally run by one of two agencies: Parks Canada, and SEPAQ. Parks Canada runs most of them from Ontario, west. Quebec considers its parks to be “national parks”, but a separate agency, SEPAQ, runs them. You cannot use a Parks Canada annual pass in a SEPAQ park, or vice versa. If you buy an annual Parks Canada pass, they will give you a list of the parks in which you can use it. Many people have also commented that SEPAQ parks are almost like provincial parks in their amenities. A common comment is that Parks Canada has free shower buildings (though you may need to put a deposit on a key, which is returned when you return the key), but SEPAQ has coin-operated showers. Camper, beware!
See also Camping Along the Trans-Canadian Highways
Atlantic Provinces
Note: Akami-Uapishk-KakKasuak-Mealy Mountains,Cape Breton Islands, Fundy, Gros Morne, Kejimkujik, Kouchibouguac, Prince Edward Island, Sable Island Reserve, Terra Nova, Torngat Mountains
Eastern Provinces (Quebec, Ontario)
Note: Aiguebelle, Bruce Peninsula, Forillon, Georgian Bay Islands, La Mauricie, Mingan Archipelago Reserve, Point Pelee, Pukaskwa, Rouge Urban, Thousand Islands
Grassland Provinces (Manitoba, Saskatchewan)
Note: Grasslands, Riding Mountain, Wapusk
Rocky Mountain Provinces (Alberta)
Note: Banff, Elk Island, Jasper, Waterton Lakes
Northern Provinces/Territories (Nunavet, Northwest Territories)
Aulavik, Auyuittuq, Naats'ihch'oh Reserve, Nahanni Reserve, Qausuittuq , Quittinirpaaq, Sirmilik, Thaidene Nene, Tuktut Nogait, Ukkasiksalik, Wood Buffalo
Far West Provinces (British Columbia, Yukon)
Note: Glacier, Gulf Islands Reserve, Gwaii Haanas Reserve, Ivvavik, Kluane National Park and Preserve, Kootenay, Mount Revelstoke, Pacific Rim, Vuntut, Yoho