If your whiteboard is magnetic, then the magnets will stick to it. Magnetic whiteboards generally have a white surface deposited on a thin metal sheet. If that metal is capable of attracting the magnet, then you can surely put magnets on it. However, some boards do not have such backing or surface, so they will not serve the purpose. So, if you are looking for magnetic boards, you should specifically ask for the same. Some websites even have filters to differentiate magnetic and non-magnetic styles.