The BBC program followed Matt Smith's departure as the 11th Doctor and Peter Capaldi's entrance as the new Time Lord.
ITV's "Downton Abbey" Christmas special, which overlapped in part with "Time of the Doctor," was seen by 7.01 million viewers, Deadline.com said.
"To the downton-abbey-christmas-special-2013Whoniverse, thanks a million. You're the best. I'll miss you. And I'll miss the madness," Smith tweeted after the programs aired.