The actor and comedian told Shortlist that the Channel 4 comedy is unlikely to follow E4's The Inbetweeners into the multiplexes.
"We've always discussed it but we feel doing a film would mean the end of the TV series," Mitchell - who plays Mark - explained.
"I think if [Peep Show's creators] Sam [Bain] and Jesse [Armstrong] decided to stop [doing the show], we might discuss a film as a last hurrah. But we've always felt we should keep the series going as long as possible."
Mitchell joked that a storyline following Mark and Jeremy (Robert Webb) heading to Barbados "wouldn't really work".
"I don't think Mark and Jeremy would choose to go on holiday together," he laughed.
The eighth series of Peep Show begins this Sunday (November 25) at 10pm on Channel 4.
> Peep Show David Mitchell and Robert Webb interview
> David Mitchell on new BBC Two sitcom: 'It's such a good subject'
Watch a clip from Peep Show below: