Is it legal to send a bottle of olive oil (unopened & sealed) from the US to Canada?

i would think it is fine. its OPEN food like fruits vegatables etc. that cause problems becaues of pests. although in one year the USA went crazy and Canadians could not even ship gum or candy to the USA unless we made it ourselves. stupid.

US Customs and Border Patrol
http://www.cbp.gov/xp/cgov/export/

correct way to complete shipper’s export
http://www.census.gov/foreign-trade/regulations/forms/correct-way-to-complete-the-sed.pdf

It should be fine, but make sure it is packed very well. You can probably pack it up in one of those boxes that comes with foam (shaped like a bottle) You can find them at Beverages and More.