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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13. Dog man and Goldilocks
Mary frank, 4, and Max Frank, 8, dressed as Goldilocks and Dog Man at Horndean Infants School for World Book Day. Photo: Christine Wyatt
14. Paddington
Arthur Cordwell, age 2, from Portsmouth dressed as Paddington Bear for World Book Day. Photo: Chelsea-Louise Gregory
15. Alice in Wonderland
Lacey-Rose, 6, from Gosport, dressed as Alice in Wonderland for World Book Day. Photo: Sammie Land
16. Deadly 60
Hugo Powell 6 from Waterlooville dressed as Steve Backshall's Deadly 60 for World Book Day Photo: Carlie J. Powell