The Queen (Queen Elizabeth II) is technically Canada's Head of State. Her representative is the Governor-General federally, and the Lieutenant-Generals provincially.
Its a relic from Canada's history. I really do hope the previous two posters were not American. If so, shame on you. (No, I'm not canadian. not even remotely so). As a foreign student in America, I'm rather surprised at how little some americans know about the rest of the world.
Anyhow, here's some information about how canadian government works.
http://www.parl.gc.ca/information/li...ves-5th_Ed.pdf