Gibb replaces Katie Perrior, who left the role in April after May called last month’s snap General Election.
Gibb announced the news on Twitter this afternoon:
I am pleased to announce I will be leaving the BBC to join the Prime Minister, Theresa May, as her new Director of Communications— Robbie Gibb (@RobbieGibb) July 6, 2017
It's been a privilege to work for the BBC. I will always be a supporter because of its values and commitment to impartiality.— Robbie Gibb (@RobbieGibb) July 6, 2017
Gibb has held the role of editor, live programmes, at BBC News since 2008.
This includes editor of BBC Daily and Sunday Politics, exec editor of both the Andrew Marr Show and This Week, and editor of BBC TV's Budget and Autumn Statement programmes.
He has worked at the BBC for 23 years - previously roles there include deputy editor of Newsnight from 2002 to 2008. Before joining the BBC, he was an adviser to Michael Portillo.
Since leaving Downing Street, Perrior has been openly critical of the Conservative Party's General Election campaign. She has since rejoined iNHouse Communications, the agency she co-founded, as chair.
Meanwhile, Gibb's successor at the BBC is Katy Searle, editor of BBC Political News.
Congrats to v talented @RobbieGibb off to No 10 top comms job. Pleased to be taking over for now as Head of BBC Westminster.— Katy Searle (@KatySearle) July 6, 2017