It's World Book Day on Thursday 5 March so lots of you will be wearing some pretty cool costumes to school.
It's a big international event, started 24 years ago, to celebrate books and reading.
The aim of it, is to give every child a book of their own.
It's organised by a charity and takes place in more than 100 countries all over the world, although some other countries actually celebrate it in April.
And to mark the occasion, loads of you are dressing up as your favourite characters or having non-uniform days at schools.
We'd love to see your costumes! Use the form below to send your pictures in.
If your parent wants to upload your photo for you then please click here.
If you can't see where to send in your World Book Day pics, then click here.