Can wallpaper be placed over wood paneling?

Yes, but realize the grooves in the paneling will show thru.

If the panelling is true wood, there is usually a ridge or grove that can be treated, either by filling the area with drywall mud and then sannding or by covering the entire surface with an under layer of wallpaper.
Your wallpaper retailer will be able to advise you.
There are also textured wallpapers, call glyptic paper that will go over paneling or badly damaged walls and cover the imperfections.
This glyptic paper will need to be painted to finish it off, but is a great way to get from old dark paneling to something new and stylish.