Authors similar to the funny fantasy author Tom Holt

Humorous fiction
P.G. Wodehouse	English author that wrote about incidents in England in the '30-'40's, his most known characters are Jeeves & Wooster.
Damon Runyon	Wrote about US during the '30-'40's, similar to P.G Wodehouse, but the setting is in US, and often involves criminal elements. I've written a review of one of his books. Runyon was a newspaper man, and all of the people in his stories are based on real people he knew. All of the stories has been date before 1950 (most are from the 20s and 30s)
Ernest Bramah	Wrote stories about a chinese storyteller named Kai Lung. The english is a bit to advanced for me, give it a try and see if you like it. Barry Hughart's Chinese Stories shall also be of interest if you enjoyed Ernest Bramah, havn't read anything by him, though.
Humorous fantasy
Terry Pratchett	He is known for his Discworld-novels, humourous fantasy. My review of Wyrd Sisters.
Robert Asprin	Humourous Fantasy, similar to Pratchett. I've written reviews of his first two novels.
James Bibby	American. I've scribbled down some comments on his novel Ronan the Barbarian.
John Brosnan	Australian, though he now lives in the UK. I've scribbled down some comments on his novel Damned & Fancy.
Humorous science fiction
Douglas Adams	Known for his 'The Hitchhikers Guide to the Galaxy', if you havn't read anything by him, you have several hours of fun before you, get started right now!
Rob Grant & Doug Naylor	British authors. Humorous science fiction. Did the novelisation of their own tv-series Red Dwarf. They have written books together as Grant Naylor. I've scribbled down some comments on their novel Red Dwarf
Phil Janes	Humorous science fiction. I've scribbled down my thoughts on his book The Galaxy Game
Robert Rankin	More science fiction than fantasy, humorous as well.
Other authors that might be interesting if you like Tom Holt Other authors that you might like, no guarantees (They are in no particular order, sort of almost alphabetical, but not quite)
Piers Anthony	From US
Dave Barry
Iain Banks
Fredric Brown	Martians Go Home
L. Sprague de Camp	The complete enchanter
Neil Gaiman	known for Sandman, has also written Good Omens together with Terry Pratchett which is the only book by Gaiman I've read, but it was relly good.
Craig Shaw Gardner	US
Andrew Harman	United Kingdom
Harry Harrison	American, living on Ireland
Dan McGirt	US
P J O'Rourke
Roger Zelazny & Robert Sheckley	(both US) who wrote three comic fantasy together: "Bring me the Head of Prince Charming" (1991) "If at Faust You Don't Succeed" (1993) "A Farce to be Reckoned With" (1995) Robert Sheckley also wrote many short stories that appeared in collections as Citizen in Space, Untouched by Human Hands, The Status Civilization, and Notions:Unlimited.
Vonnegut	The Sirens of Titan
R.A. Lafferty
John Brunner	"Traveller in Black"
Thorne Smith	"Rain in the Doorway" and "The Bishops jaegers"
Tom Sharpe	Known for his stories about Wilt.

Ring Lardner, and James Thurber were two american short story writers. Their stories takes place in the 1920s-1940s. Thurber's most famous story, "The Secret Life of Walter Mitty" was made into a movie with Danny Kaye in the late 40s, early 50s.
They are both supposed to write in similar style to Damon Runyon and P.G. Wodehouse

Eli Salmon has contributed with much stuff to this page, and also wrote this to me about some other authors:

Norman Spinrad also wrote some very funny crazy short stories a long time ago about cavemen inventing interior decoration and the government inventing hallucinogenic drugs with odd side effects that spacemen can use so they won't go crazy during very long interstellar flights. I think they appeared in collections with other authors and I find his other work much less funny. Somehow (perhaps intentionally) you managed to leave out Fritz Lieber and his Fafhrd and Gray Mouser stories (e.g. Ill Met in Lahkmar) among other stories, Keith Laumer and his Retief stories (for example Retief and the Pangalactic Pageant of Pulchritude,) and Stanislaw Lem and his pilots and constructors (for example The Cyberiad.)