The 50-year-old author published her final Harry Potter novel in 2007, and has since branched out into adult literature, including writing crime novels under the pseudonym Robert Galbraith.
"I'm not going to give you an absolute date because things are busy and I've been writing a screenplay as well. But I will definitely write more novels under J K Rowling. I've written part of a children's book, which I really love. I will definitely finish that. I have ideas for other adult books," Rowling told BBC.
Tickets for Rowling's play, 'Harry Potter and the Cursed Child', which is set 19 years after the completion of the novels, went on sale last week.
"I've always said I'm not going to say never because there were things in my head about 19 years later. I had no desire to write it as a novel, for reasons that will be clear. This play never would have happened if this particular team hadn't come to me. I didn't go looking for this," she said.
She said the she finds it "genuinely liberating" to write under a pseudonym, and that she was sad when her identity was revealed, as she wanted the books to be "a little bit less about the hype".