You can paint over wallpaper, but the tint won't look like what you bought in the store and it will take at least 3 coats to cover. Also, the people that move into the house after you wants to remodel, they will have to remove the paint & wallpaper, it's a huge job. Best to remove the wallpaper and then paint. Also, if the wallpaper has any puckers in it, it will eventually crack the paint.