We have been inundated with a wealth of fantastic photos after putting out an appeal for them on Facebook.
This gallery has been updated throughout the day as more and more pictures have been sent over!
MORE: Best World Book Day photos from 2021, World Book Day excitement grips Portsmouth as children become their favourite superheroes
Unfortunately due to the overwhelming amount of photos we were sent and time constraints, we have not been able to feature every single one sent to us today – despite hoping to be able to do so.
But we tried to feature as many as possible - and there are over 50 images in our gallery!
The gallery is at the bottom of this article – and make sure to click through all the pages!
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1. Superworm and Peter Pan
Fleur Cross, 1, whose favourite book is Superworm. And Jude Cross, 5, whose favourite book is Peter Pan. Dressed up for World Book Day. Photo: Jordan Cross
2. Cat in the hat and Queen of Hearts
Katie aged 11 as Cat in the Hat and Sophie age 8 Queen of Hearts from emsworth Photo: Kim Whitehouse
3. Paper dress up doll
Chloe age 5 from Portchester dressed as Paper Dress up Doll for World Book Day. Photo: Kerry Harvey
4. Jughead Jones
Indigo-Violet age 9 from Fratton dressed as Jughead Jones from the Archie comics for World Book Day. Photo: Naomi Peta Tubbritt