The sitcom ran for three series between 2007 and 2010 and there have long been rumours of a return or a musical special.
Despite previously suggesting a one-off episode set in Spain, Page last month told Digital Spy that "it would be a nightmare trying to get everyone back together again".
Asked if there would ever be any more Gavin & Stacey, Page told Metro: "No. It's all over now."
Of whether it was a relief that the show was over, she added: "Not a relief, but it's a job like any other.
"You have a great time filming with everyone and then it finishes and you move on to the next thing. That's what I like as an actor - not knowing what's coming next."
Asked about people's misconceptions of her, Page added: "People think I'm sweet and giggly and exactly like my character in Gavin & Stacey, and I'm not."
Ruth Jones has said that there were "no plans" to make any more episodes as she and co-star and co-writer James Corden were both "really busy".
Corden has brushed off claims that he said there will "definitely" be a comeback, but also added "maybe one day".
Watch a clip of Joanna Page in Gavin & Stacey below: