Nanny Plum is the main tritagonist in the series. She is a fairy residing in the Little Kingdom. She works as a housekeeper for the Little Castle, and is also Princess Holly's caretaker.
Nanny Plum comes off as sarcastic and cynical; at times being dismissive to authority. She can generally immature and is typically carefree about her actions. Despite this, she can be very friendly and helpful, especially towards Holly.
She rivals with the Wise Old Elf due to their differing opinions over the use of magic.
She has short black hair tied in a half bun. Her bangs are in a short 'baby' style. She wears a long purple dress, purple shoes and is always seen with her wand.
- She is capable of speaking many animal languages including Ladybug and Chicken, but cannot speak several of the more difficult languages, such as Mole and Aardvark.
- She likes vegetables, especially peas.
- She currently runs the official Ben & Holly twitter.