Storing olive oil so that it remains fresh, retains flavor, and doesn’t go rancid is important, especially with special and expensive oils that are used only occasionally. Everyday olive oil is used up fast enough that that it’s usually not a problem.
The question is whether to refrigerate or keep in a kitchen cabinet. Harold McGee, renowned food scientist, says in it makes no difference; olive oil spoils at the same rate in or out of the fridge.
See what he has to say about it: Harold McGee speaks.
Your experience may be different, if you live in a hot climate or your kitchen stays warm. Olive oil likes to be cool and in a dark place. The fridge will accomplish both. If the bottle hasn’t been opened to admit air, either choice could be OK. Olive oil should be brought to room temperature before using, however.