The Festival Fan Book is a fanbook that was inserted in pre-orders of volume 12 of the Haganai manga series. Limited versions of the pre-order came with a hard-cover box that contained the Festival Fan Book. The cover features Thomas the Tank Engine inspired art. It has Sena Kashiwazaki as Thomas, Kodaka Hasegawa as Toby and Yozora Mikazuki as James.
The Festival Fan Book includes a special manga chapter, a special light novel-esque chapter written by the original author and some manga artwork.