The drone struck in Barmal area of South Waziristan tribal agency, TV news channels quoted officials as saying.
The spy planes fired four missiles at the house, where militants had gathered to condole the death of a commander killed in another drone strike yesterday.
At least 10 of them were killed and several others were injured, local residents said.
The house caught fire after the missiles slammed into it.
TV news channels quoted officials as saying that some foreign militants were among those killed.
Reports said that the dead men belonged to a Taliban faction led by Mullah Nazir.
Two commanders of the faction were killed in yesterday's drone attack.
There have been seven drone strikes since May 23.
Most of the strikes were carried out in North Waziristan, described by US and Afghan officials as a safe haven for Taliban and al-Qaeda elements.
Since yesterday, the drone strikes have focussed on South Waziristan, where Pakistan army had conducted an operation to flush out the Taliban three years ago.
The US stepped up drone strikes shortly after the conclusion of the NATO Summit in Chicago, where Pakistan did not make any announcement about ending a six-month blockade of supply routes to Afghanistan.
The supply lines were shut after a cross-border NATO air strike killed 24 Pakistani soldiers in November last year.
The drone strikes have added to tensions between the US and Pakistan, which has described the attacks as a violation of its sovereignty and called for them to be stopped.
Over 130 people, mostly militants, have been killed in drone strikes this year.
The US had eased its drone campaign in Pakistan's tribal areas after a CIA contractor was arrested for shooting and killing two Pakistani men in Lahore early last year and the unilateral American raid that killed Osama bin Laden in Abbottabad in May last year.