From Oompa Loompas to Paddington Bear, all sorts of colourful characters have emerged.
Some made their own costumes, and one school even saw pupils designing their own t-shirts.
Shaylea and Shaneice O’Brien, aged 10 and eight, as Matilda and Alice In Wonderland. Pupils at Ashleigh CofE Primary School .
Another reader instead sent in a photo of potatoes which children had been decorating as characters.
And at Park Community School, it was role-reversal once again as staff and teachers dressed up instead of students.
Lewis Ten-Bokkel, aged 6, as Captain America and Bradley Ten-Bokkel, ages eight, who designed his own t-shirt from Diary of a Wimpy Kid. Pupils at Pilton Bluecoat and Pilton Infants School.
Scroll down to see more fantastic costumes for World Book Day today from our Facebook page.
Mitch Davey, aged eight, from Ilfracombe Junior School Piper Davey, aged five, from Ilfracombe Infants. Joseph Prentice, nine, from Ilfracombe Juniors Jack Orpen, aged seven, from Southmead Primary in Braunton, as Fantastic Mr Fox Murph from Kid Normal (Tom Smith age 9 from Ilfracombe Junior School) and Spiderman (George Smith age 5 from Ilfracombe Infants) Amie age eight, as Hermione Granger. Josie age six as Sophie from The Tiger Who Came to Tea - Both from South Molton Community Primary. Riley, age two as Little Monster, from Tarka Tots, South Molton. Maci, aged seven and Bailey-Jorge, aged five, from Ilfracombe Juniors and Infants. Sam Huxtable sent in this picture of decorated potato characters instead! Harvey Clayton, aged six, Ellie Clayton, aged 10, and Dillan Clayton, aged nine, all pupils Yeo Valley Primary. Jaidan Passmore, aged nine, as Toothless. Emily Beer, aged six, from Newport Primary. Ashley Prentice, aged four, from Ilfracombe Infants. Theodore Baxendale, age seven, atIlfracombe Junior School dressed as Horrid Henry in Football Friend, complete with secret prank box! Charlie Beer, aged 10, from Newport Primary. Luke Lancey, aged 10, from Ilfracombe Junior School, dressed as an Oompa Loompa. Harry Lancey, aged eight, from Ilfracombe Junior School, dressed as Paddington Bear. Amelia Harvey, ages six, from Yeo Valley School. Joshua Hayes, aged 8, going to school as Mr Stink. Scarlett Wilson, aged 6, going to school as Gangsta Granny. Brooklyn and Harley Jenkins, going as Mario and Luigi, to Sticklepath School. Jordan Bennett, aged four, at Eden Park Academy.