The writer said that there was "no chance" of the broadcaster "giving up" on the sci-fi drama, in an interview on BBC Radio 5's Richard Bacon Show.
"It's a huge money-spinner," Moffat explained. "It's doing better than ever abroad - the global number of people watching Doctor Who has just gone up and up and up.
"It was the most downloaded show on American iTunes last year - [there's] not a chance of the BBC giving up on Doctor Who, not at all."
Moffat also dismissed the suggestion that viewers were getting "shorter and shorter seasons" of the programme.
"We're just splitting it over Christmas, we're making the same number of episodes as usual," he said. "We delayed it a few months to start it later in the year, that's all that's happened."
The seventh series of Doctor Who will introduce a new companion, with Moffat describing the arrival of actress Jenna-Louise Coleman as "very exciting".
"When a new companion comes in it sort of reboots the show a little bit, it makes you look at the Doctor differently, it makes the show feel different," he suggested.
"It's literally a new beginning, you're back to chapter one - in a way [the show is] always a story of someone getting to know the Doctor, and now it's Jenna's character."
The showrunner went on to praise Coleman, calling the 26-year-old "wonderful and spiky and salty and clever".
"I'm thrilled with her - everyone's going to be," he said.
Doctor Who will return to BBC One in the autumn, with the series seven premiere debuting at this year's Edinburgh International Television Festival.
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Watch a trailer for the next series of Doctor Who below: