He doesn’t seem to be stopping there though – there’s a brand new book out now called Horrid Henry’s Krazy Ketchup.
And to celebrate his birthday, there’s a brand new 20th anniversary edition of the very first Horrid Henry book with a brand new section called 20 Things You Didn’t Know About Horrid Henry.
Since it’s his birthday we asked you tell us your favourite ever Horrid Henry moment!
Absolutely loads of you got in touch and here are some of our favourites!
Horrid Henry stories by Francesca Simon. Illustrations © Tony Ross. Published by Orion Children’s Books.