Can I paint over old wallpaper in a small bathroom?

You can but you will need to make sure it is clean and completely sealed. If there are any spots where the wallpaper is coming loose, it won't look good. Once you clean it then prime and paint.

Is there a reason you aren't removing? It isn't as difficult as you might think. I've removed it from many rooms, even paper that was glued & pasted vinyl.

Although it is 'possible' to do this, I would dissuade you from doing so.

A bathroom is exposed to a great deal of moisture. If the wallpaper is old, you do not know what the condition of the walls are behind it. Adding an additional layer of paint my just be increasing the problems you will have down the road.

Read through some of the postings here on Hometalk from others who are now faced with the huge job of having to remove painted wallpaper. Perhaps this will convince you of the wisdom in removing the wallpaper first before painting.

Clean, seal the wallpaper, then prime and paint.

If you have any seams that are loose it won't look good.

You might want to consider removing first.

Always best to remove it. Moisture in the paint can cause it to bubble or separate. ASeams will show. A pain in the butt to remove in the future. If you must paint. Wash it down well. Prime with Kilz primer then paint your color. Good luck.