Smith was honoured with the award for 'Best Performance By An Actress In A Supporting Role In A Series, Miniseries or Motion Picture Made For Television' at Sunday evening's (January 13) ceremony.
> Golden Globes 2013: All the TV winners from 70th annual awards
Smith was rewarded for her role as Violet, the Dowager Countess of Grantham, on the Julian Fellowes-created series. She was not able to attend the ceremony, and the trophy was accepted on her behalf by Kerry Washington and Dennis Quaid.
This is the third Golden Globe award for Smith, who has previously won for her roles in California Suite and A Room With a View.
She was also nominated this year for the movie Quartet, losing out to Jennifer Lawrence for Silver Linings Playbook.
Downton Abbey's third season is now airing on PBS in the US. A fourth series has been commissioned by ITV.
Watch Maggie Smith in the series three trailer for Downton Abbey below:
Photo gallery - Golden Globes winners in pictures: