It's World Book Day, an annual event designed to encourage parents to read to their kids, as well as an opportunity for children top dress up as some of their favourite characters from literature, from the Gruffalo to Cinderella.

Organised by UNESCO, it's been celebrated by families and schools in over 100 countries all over the world for the past 16 years.

As well as dressing up youngsters as their favourite literary character, parents are provided with vouchers they can exchange for eight different titles at their local book shop. In the UK, more than 14 million vouchers as distributed - which is one for nearly every child aged under 18 in the country!

world book day

Here are some of the costumes you've sent in. To include your child in the gallery, email a picture to ukpicturedesk@huffingtonpost.com or tweet @HuffPostUKPics

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  • Children dress up for world book day

    @BeccyHol: Libby as Elmer for #WorldBookDay. She loves her Elmer books so much. To include your child in the gallery, email a picture to <a href="ukpicturedesk@huffingtonpost.com">ukpicturedesk@huffingtonpost.com </a>or tweet <a href="https://twitter.com/HuffPostUKPics">@HuffPostUKPics </a>

  • Children dress up for world book day

    Harry and Ethan as Spider-Men

  • Children dress up for world book day

    Enas Filimban - My 2 kids are in West Jesmond Primary School in Newcastle Upon Tyne. One is dressed as Batman and the other is dressed as a vegetable because of Oliver's Vegetable's story.

  • Children dress up for world book day

    FourGoMad @FourGoMad #worldbookday Andy Stanton's Mr Gum mrgum.co.uk

  • Children dress up for world book day

    FourGoMad @FourGoMad #worldbookday Enid Blyton's Darrel Rivers from Malory Towers

  • Children dress up for world book day

    cherrypress @roald_dahl thanks for the inspiration for #worldbookday #theenormouscrocodile To include your child in the gallery, email a picture to <a href="ukpicturedesk@huffingtonpost.com">ukpicturedesk@huffingtonpost.com </a>or tweet <a href="https://twitter.com/HuffPostUKPics">@HuffPostUKPics </a>

  • Children dress up for world book day

    Unfortunately Seth is off school ill but he is still wearing his costume! #WorldBookDay #MrTickle

  • Children dress up for world book day

    Tommy Storey @Hunkchunkalmond my kids went as a death eater from Harry Potter and Rapunzel #worldbookday To include your child in the gallery, email a picture to <a href="ukpicturedesk@huffingtonpost.com">ukpicturedesk@huffingtonpost.com </a>or tweet <a href="https://twitter.com/HuffPostUKPics">@HuffPostUKPics </a>

  • Children dress up for world book day

    Tahera Ali @lahorilond death eater in stoke newington! To include your child in the gallery, email a picture to <a href="ukpicturedesk@huffingtonpost.com">ukpicturedesk@huffingtonpost.com </a>or tweet <a href="https://twitter.com/HuffPostUKPics">@HuffPostUKPics </a>

  • Children dress up for world book day

    Coleen Rooney ‏@ColeenRoo World Book Day!!! The Mad Hatter!!! To include your child in the gallery, email a picture to <a href="ukpicturedesk@huffingtonpost.com">ukpicturedesk@huffingtonpost.com </a>or tweet <a href="https://twitter.com/HuffPostUKPics">@HuffPostUKPics </a>

  • Children dress up for world book day

    megsnoli Room on the broom witch for world book day :) #worldbookday #roomonthebroom #juliadonaldson #favouritestory #witch #broomstick xx To include your child in the gallery, email a picture to <a href="ukpicturedesk@huffingtonpost.com">ukpicturedesk@huffingtonpost.com </a>or tweet <a href="https://twitter.com/HuffPostUKPics">@HuffPostUKPics </a>

  • Children dress up for world book day

    kazzamallazza Jack and the beanstalk #worldbookday To include your child in the gallery, email a picture to <a href="ukpicturedesk@huffingtonpost.com">ukpicturedesk@huffingtonpost.com </a>or tweet <a href="https://twitter.com/HuffPostUKPics">@HuffPostUKPics </a>

  • Children dress up for world book day

    kate_meagh Legit Harry P #worldbookday #littlebrother To include your child in the gallery, email a picture to <a href="ukpicturedesk@huffingtonpost.com">ukpicturedesk@huffingtonpost.com </a>or tweet <a href="https://twitter.com/HuffPostUKPics">@HuffPostUKPics </a>

  • Children dress up for world book day

    fizzpopbangblog Benjamin Bunny. World Book Day Costume. To include your child in the gallery, email a picture to <a href="ukpicturedesk@huffingtonpost.com">ukpicturedesk@huffingtonpost.com </a>or tweet <a href="https://twitter.com/HuffPostUKPics">@HuffPostUKPics </a>

  • Children dress up for world book day

    Steph Weaver ☆ @StephoDub @HuffPostUKPics #worldbookday thing 1 and thing 2 :) To include your child in the gallery, email a picture to <a href="ukpicturedesk@huffingtonpost.com">ukpicturedesk@huffingtonpost.com </a>or tweet <a href="https://twitter.com/HuffPostUKPics">@HuffPostUKPics </a>

  • Children dress up for world book day

    lilmisstamsin #pirates for #worldbookday

  • Children dress up for world book day

    caitlin_26 my dwarfs being sad cause the evil queen poisoned me!! #worldbookday #snowwhite #7dwarfs

  • Children dress up for world book day

    lloydielloyd #gandalf & #skullduggerypleasant #worldbookday

  • Children dress up for world book day

    miss_lou84 Kayden and Riley

  • Children dress up for world book day

    lisalong #worldbookday #pirate

  • Children dress up for world book day

    franksyx My Wally #worldbookday #son #love #wally ❤

  • Children dress up for world book day

    paulamoo My DIY Dementor costume for son's school #worldbookday made from charity shop skirts.

  • Children dress up for world book day

    sweet84kisses World book day!!! My failed attempt of African animals well LIon king and lion queen GWT IT🙈 #worldbookday #school #twins #lionking #lionqueen #mummyshitatfacepaint #macmakeup #stressed #needafag #neveragaib #london

  • Children dress up for world book day

    jennifermcmanus World book day ... #WorldBookDay #MarvelComics #CaptainAmerica #Nephew #DressUp

  • Children dress up for world book day

    Mr Stink on #WorldBookDay!

  • Children dress up for world book day

    Faber Children's @FaberChildrens Happy #WorldBookDay - here are Harry Potter and Bilbo Baggins on their way to school! pic.twitter.com/NiDzGLVr56

  • Children dress up for world book day

    Faber Children's @FaberChildrens We've got a gorgeous little Angelina Ballerina for #WorldBookDay here. Who have you dressed up as?

  • Children dress up for world book day

    And finally Bilbo Baggins WITH a fairy princess for #WorldBookDay

  • Children dress up for world book day

    Don't you know? There IS such a thing as a Gruffalo! Happy #WorldBookDay

  • Children dress up for world book day

    Marina Hicklin @picklehic My son went as Harry Potter #worldbookday.

  • Children dress up for world book day

    picklehic Marina Hicklin 1 min Original Willy Wonka #worldbookday.

  • Children dress up for world book day

    Kate @QueenMOOdyCow My three always root for the bad guys, hence two death eaters and my girl as Draco Malfoy

  • Children dress up for world book day

    RebeccaAshdownPetrie @FamilyOfBeasts #worldbookday Pippi Longstocking! The strongest girl in the world!