Here's why:
* Dystopian: The story takes place in a future society that is oppressive and unjust. The Capitol controls Panem, the nation, with an iron fist, and the citizens are subject to strict rules and constant surveillance.
* Science Fiction: The story involves advanced technology like the Hunger Games arena and the Capitol's sophisticated weaponry.
While *Mockingjay* also has elements of young adult fiction (due to its main characters' ages and themes of coming-of-age), the dystopian and sci-fi aspects are dominant.