The Old Kingdom, or Abhorsen in North America, is a fantasy fiction series by Australian author Garth Nix. It originated in 1995 with the novel Sabriel and has continued in novels Lirael (2001) and Abhorsen (2003), novella The Creature of the Case (2005), and other short fiction. In Australia the omnibus edition comprising three novels and one novella was titled The Old Kingdom Chronicles (2009, Allen & Unwin (Australia)). U.S. omnibus editions have been titled The Abhorsen Trilogy (2003) and The Abhorsen Chronicles (2009). ISFDB catalogues the entire continuing series as "The Old Kingdom / Abhorsen".
Nix has announced two more Old Kingdom books, a prequel and a "sequel of sorts to Abhorsen" (below).