The actor, who plays Jeremy in the Channel 4 sitcom, told Digital Spy that the team are "delighted" with the end result.
Asked if the show is becoming stale after five series, Webb said: "Sam [Bain] and Jesse [Armstrong] work incredibly hard to make sure the show is in order. I think it just gets better every time. We're all delighted."
His co-star David Mitchell added: "I really feel that the sixth series is as good as any. Obviously we're terrified of it becoming stale but I think so far that terror has been averted."
Earlier this month, Mitchell and Webb confirmed that a seventh series is currently being written. Discussing a possible eighth run, Mitchell admitted that there may be a hiatus after the seventh series airs.
"There's been some talk of [an eighth series]," Mitchell revealed. "I think it's in the hands of Sam, Jesse and Channel 4. I think Rob and I will carry on doing the show as long as we can but Sam and Jesse have got other writing things and Peep Show takes most of their year up when it happens.
"I don't know - there may well be more, but I don't think there'll be an eighth series hot on the heels of the seventh. I think there'll be a hiatus. Or at least a sabbatical."
The sixth series of Peep Show begins tonight at 10pm on Channel 4.
> Click here to read our full interview with Mitchell and Webb