From classic fairytales and Roald Dahl favourites - to Harry Potter characters and comic book superheroes – parents have pulled out all the stops to dress up their children this year.
World Book Day is an annual event run by a charity that operates in the UK and Ireland celebrated in 100 countries around the globe.
Its mission is to promote reading for pleasure by offering every child and young person the opportunity to have a book of their own.
Here are a selection of photos of youngsters celebrating World Book Day, which were sent in to the Boston Standard.
33. Posted to Boston Standard's Facebook
Children dressed as colourful characters for World Book Day. Photo: Images supplied
34. Posted to Boston Standard's Facebook
Children dressed as colourful characters for World Book Day. Photo: Images supplied
35. Posted to Boston Standard's Facebook
Siblings dressed as different book characters ready for World Book Day. Photo: Images supplied
36. Minecraft
Finley Seymour, five, of Boston, as Steve from Minecraft, with one of his favourite books - Minecraft: Beginner's Handbook. Photo: Image supplied