Gaslamp fantasy (also known as gaslight fantasy or gaslight romance) is a subgenre of both fantasy and historical fiction. Generally speaking, this particular realm of fantasy employs either a Victorian or Edwardian setting. The gaslamp fantasy genre is not to be confused with steampunk, which usually has more of a super-science edge and uchronic tone. Gaslamp fantasy also differs from classical Victorian/Edwardian faerie or pure fantasy in the J.R.R. Tolkien or Lewis Carroll style or from historical crime-novels in the Anne Perry or June Thomson style by the supernatural elements, themes, and subjects it features. Many of its tropes, themes, and stock characters derive from Gothic literature — a long-established genre composed of both romantic and horrific traits and motivated by the desire to rouse fear, apprehension, and other intense emotions within the reader — and could be described as an attempt to modernize literary Gothicism.
Writer and artist Kaja Foglio originally coined the term in an effort to distinguish her and husband Phil Foglio's comic series, Girl Genius, from "steampunk". Kaja hoped to suggest the work's distinctive style, a medley of alternate history and Victorian-esque "mad science".
Later on, however, fantasy-fans redirected the term to denote a spin-off genre of Holmesian fantasy or Victorian-based Gothic tales. According to fantasy-fans as a whole, the subgenre consists, namely, of contemporary or modern fantasy pieces set in the Victorian "gaslamp" era. However, the subgenre also includes some works with a pre-Victorian setting (Susanna Clarke's Regency novel Jonathan Strange & Mr Norrell, for example). More samplings of the genre can be found in publications such as the Gaslight Grimoire anthologies and The League of Extraordinary Gentlemen comics.