Teachers and children in Worthing have been dressing up, with costumes including Slinky Malinki, Cruella de Vil with her dalmatians, the Hungry Caterpillar and Tom from Tots TV.
It is a particularly special day for brothers Blake Heppenstall, 11, and brother Ellis Heppenstall, eight St John the Baptist School in Findon. Blake dressed as Marty McFly and Ellis as Dr Emmett Brown.
Mum Dani Heppenstall said: "Both my boys wanted to create and they have spent time making their very own DeLorean as this is their last World Book Day together, as Blake will be leaving for high school in September."
1. World Book Day
Blake Heppenstall, 11, dressed as Marty McFly and brother Ellis Heppenstall, eight, as Dr Emmett Brown Photo: Dani Heppenstall
2. World Book Day
Blake Heppenstall, 11, dressed as Marty McFly and brother Ellis Heppenstall, eight, as Dr Emmett Brown Photo: Dani Heppenstall
3. World Book Day
Blake Heppenstall, 11, dressed as Marty McFly and brother Ellis Heppenstall, eight, as Dr Emmett Brown Photo: Dani Heppenstall
4. World Book Day
Victoria Emerson sent in this photo of her six-year-old Aria from Vale School in Findon Valley. She is Elton John, inspired by the Little People, Big Dreams book. Photo: Victoria Emerson