The government may have broken parliamentary rules by failing to fully release legal advice over the Brexit deal, according to John Bercow.
The prime minister lost a government motion heading off the demand for the legal advice by four votes, 311 votes to 307.
Leader of the House Andrea Leadsom confirmed that the government would respond promptly on Wednesday.
It had tried to head off the contempt vote with an amendment that would have sent the issue off to consideration by a parliamentary committee.
The vote has little direct impact on the Brexit debate, but reflects mounting tension between the government and Parliament over the next steps in Brexit.
Monday's angry session of Parliament did not bode well for the December 11 vote, which will come at the end of five days of bruising debate starting on Tuesday.
Rejecting it would leave the United Kingdom facing the prospect of a chaotic "no-deal" Brexit, but May's chances of winning majority backing for the deal appear slim.
Once the results of the two votes were announced, Labour's Keir Starmer described the situation as "unprecedented" and noted that the legal advice must now be published in full.
"Today's finding of contempt is a badge of shame for this Government".
Chris Leslie, the Labour backbencher backing the amendment, said: "MPs are going to gradually assert their rights - including the right to instruct the government in future stages".
Bank of England Governor Mark Carney said Tuesday that British consumers could see their weekly supermarket bills up by 10 percent in a worst-case Brexit scenario that involves a 25 percent fall in the value of the pound.
Britain's Prime Minister Theresa May answers questions about her Brexit agenda at a Parliamentary liaison committee meeting, November 29, 2018 in London.
Under the terms of the EU Withdrawal Act, the government will have 21 days to come back to parliament with a motion, setting out what it plans to do.
May's has long warned lawmakers that if they do not back her deal, they could open the door to Britain falling out of the European Union without any measures deal to soften the transition, or that Brexit might not happen.
"This deal.is the best way, I firmly believe, of ensuring that we leave the European Union on March 29", Attorney General Geoffrey Cox told parliament on Monday.
Since the Commons debate, Lib Dem spokesman Tom Brake said Mr Cox should be suspended if he is found in contempt of Parliament.