"Completely fabricated," he said.
ESPN's Buster Olney created a stir Monday when he wrote that dissension and unrest persisted within the Boston clubhouse, a notion the Sox vehemently denied before Tuesday's series opener against Miami at Fenway Park.
"I don't know where people get that from," said Beckett, who had declined to speak to the media after each of his past two starts. "I think people want that to be the case, and I just don't think it is.
"I think there are certain people, they want it to be that way, so they report it that way."
Beckett called the Sox clubhouse "one of the tightest-knit groups" he has ever been a part of, pointing to team dinners on the road as an example.
"We don't pay too much attention to it," Beckett said. "The only time we have to deal with it is when we answer questions. This is a great group of guys."
Outfielder Cody Ross echoed Beckett's comments, saying the clubhouse contains a "good vibe."
Ross said that, with as much national media exposure as the Red Sox receive, such reports can come with the territory.
"It was actually comical," said Ross, who will start in his first game back from the 15-day DL. "This is the Boston Red Sox. We expect this. If we're another team, where we weren't as much in the spotlight, maybe it might hurt our feelings. But this is the Red Sox. This is expected. People are going to say stuff about us.
"But we pay no attention to it."