The period drama, which will conclude its fifth series this week, will return for a new series next year, reported Daily Mirror.
Producer Gareth Neame said, "We have had an amazing reaction to the story lines, acting and production values of Downton Abbey this year and the whole team is thrilled to be moving ahead with a new season of the show. This will provide audiences with a fresh opportunity to see what will befall our much loved characters."
ITV's director of drama Steve November added, "It is fantastic that Downton continues to be such a phenomenon - still the most popular drama on ITV in its fifth series - and we are thrilled to have commissioned a sixth series.