Turtle All The Way Down is another novel by John Green. It was released on October 10th, 2017.  It is his fifth solo novel, and his seventh overall. It was announced during VidCon 2017.

16-year-old Aza Holmes is a high school student living with OCD who ends up on a search for a fugitive billionaire. The only other details of the plot revealed to the public before release were that it was to contain, either literally or figuratively, a tuatara, Star Wars fanfiction, an unexpected reunion, friendship and values of life.

In the months leading up to the novel's announcement, Green left various clues in his weekly Vlogbrothers videos, whereupon some members of Nerdfighteria worked together to solve these hints and reveal more information about the book. That has now become an online community to dicuss the books, called Tuataria.

A section of the novel was read aloud during the Project for Awesome live stream in December 2016. He posted a video of himself narrating the first chapter of the novel on his channel 'Vlogbrothers'.

On December 5, 2017, John uploaded a video to vlogbrothers called On the Movies in which he announced Turtles All the Way Down would be made into a movie.