Speaking in an online chat at Reddit, Linehan explained that he wants the comedy to go out on a high.
"I'll say right off the bat... the bad news is no IT Crowd series five," he said.
Responding to questions from fans, Linehan admitted that he would "never say never" to another series but he is "just not feeling it" at the moment.
"[The] chief reason was the fact that I just wasn't looking forward to it the way I used to," he said. "I felt that the last series was a nice strong point to go out on, and anything further might just be running on the spot. You don't do your best work when you're running on the spot."
Linehan continued: "It feels like a natural time to wind things down. Apart from anything else, we're probably reaching that stage where it begins to feel odd that Roy, Jen and Moss are still stuck down in that basement. I don't want to start giving everybody babies to make it feel like they're moving on with their lives. My kind of comedy has always been setpiece-driven... and maybe that kind of thing has a naturally short life."
However, Linehan also revealed that he is planning a special, which will air on Channel 4 next year.
"[It's] a big juicy story with great storylines for all the characters (I think)," he said, adding that he would consider making an IT Crowd film.
"It all depends on whether I come up with a good idea for one," he said. "One good enough to attract all the cast. It needs to deserve to be a film, though. So it's got to be big on all sorts of different levels.
"But even if that doesn't happen, I'm quite interested in the idea of the 'IT Crowd universe'. Like the DC or Marvel Universes. You know, maybe catching up with Bennie Wong as Prime or Douglas's Big Spaceology Wedding... these might end up just being future specials."
Linehan also revealed that he would support a rumoured crossover between The IT Crowd and US sitcom Community.
"Wasn't it something about Moss meeting Abed?" he said. "I don't see why not. [Community] creator Dan [Harmon] is someone I would trust completely with the character."
The IT Crowd, which starred Katherine Parkinson, Chris O'Dowd and Richard Ayoade, was expected to end soon but was widely thought to be getting one last series.
The comedy won a BAFTA in 2009.