How long does it take for a oil painting to dry?

I am doing an art project for school with (Reeves) oil paint on canvas covering a board. I am not much of an artist, and I usually just use the school's normal paint, which takes about a hour to dry. My oil painting has been done for a night now, but it is still not dry. How long will it take? I want it to be ready so I can take it to school on Tuesday...