It is a day to celebrate books and reading and school children typically dress up as their favourite book character.
Have a look at some of the children in Derry dressed up today.
41. The Tiger who went to tea
The Tiger who went to tea enjoying some tea and cake.
43. Pinnociho and The Cheshire Cat
Jack as Pinnociho and Eimear The Cheshire Cat
44. Stickwoman
Caitlín as Stickwoman. Caitlín made this costume, with help from her daddy, out of recycled cardboard.