That Pesky Rat is a British children's picture book written and illustrated by Lauren Child and published by Orchard UK in 2002. It won the Nestlé Smarties Book Prize in ages category 6–8 years^[2] and it was commended runner up for the Kate Greenaway Medal from the professional librarians, recognising the year's best-illustrated British children's book.^{[3][4][lower-alpha 1]}

Candlewick Press published a US edition in the same year.^[1]

In 2008, a special UNESCO edition was published in the UK. All author and publisher profits from this book now go to support UNESCO projects around the world.^{[citation needed]}

The story is narrated by a rat who wishes he could live the life of a proper pet. He visits several friends who are proper pets, including a chinchilla and a cat. However, he doesn't like the way any of them live. In the end, he puts up signs, asking if there is any one who wants a rat as a pet, and goes to a pet store. He is finally taken home from the store by an old man with poor eyesight who sees him in the display window and mistakes him for a cat. In the end, the rat says that he doesn't mind pretending to be a cat and that he likes his life as a pet.