So technically, "Kill Bill" is his 4th film directing. The one film he disowns, is his original premiere "My Best Friends Birthday" made in 1987, but as this was never officially released to cinemas, and msot of the footage has long been deleted, QT doesn't count it anymore.
He has also contributed either acting, technical assistance, film-geek knowledge and fan-assistance, script, production, or semi-directorial duties to...
Once Upon a Time in Mexico
Seul contre tous
Jackie Chan: My Story
Full Tilt Boogie: "Behind The Scens of From Dusk Till Dawn"
Saturday Night Live
The Golden Girls
"ER" (Season 1 - Motherhood)
Crimson Tide - script-rewrites
Natural Born Killers - script
Iron Monkey (1993)
From Dusk Till Dawn 3: The Hangman's Daughter
From Dusk Till Dawn 2: Texas Blood Money
No its his fifth film officialy in that he has directed, on his own, "My Best Friend's Birthday". He tries to distance himself from that one because its not like his latter work i.e. any good. He did some early films I think i heard something about a Kill Bull recently. But where do you stop counting, Guys like him make films before they become famous so do you count all those as they are films in their own right? If the guy says its fourth who are us less mortals to argue with him. Anyone seen Vol.2 yet?