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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33. Goblin King
Keelen age 9 from Copnor dressed as Jareth from the labyrinth - also known as the Goblin King - for World Book Day. Photo: Charlie Marie
34. Alice in Wonderland
Bella Neville Age 6 from Baffins dressed as Alice in Wonderland for World Book Day. Photo: Suzanne Neville
35. Elsa
Robyn Hansford age 3 Portsmouth dressed as Elsa from Frozen for World Book Day Photo: Sophie Boden
36. Room on the Broom
Olivia Hansford age 7 Portsmouth dressed as the witch from Room on the Broom for World Book Day. Photo: Sophie Boden