Allegiant is a science fiction novel for young adults, written by the American author Veronica Roth and published by HarperCollins in October 2013. It completes the Divergent trilogy that Roth started with her debut novel Divergent in 2011. The book is written from the perspective of both Beatrice (Tris) and Tobias (Four). Following the revelations of the previous novel, they journey past the city's boundaries to discover what lies beyond.
Allegiant was published simultaneously by Katherine Tegen Books and HarperCollins Children's Books in the UK. Four weeks earlier, a free electronic companion book to the trilogy titled The World of Divergent: The Path to Allegiant was released online. The novel is being adapted into a two part film, the first part of which was released on March 18, 2016, while the second part, called Ascendant, is currently in development.