13 December 2018 07:33 am
After securing 63% of the total vote, she is now immune from a leadership challenge for a year.
Speaking in Downing Street, she vowed to deliver the Brexit "people voted for" but said she had listened to the concerns of MPs who voted against her.
Her supporters urged the party to move on but critics said losing the support of a third of MPs was "devastating".
The prime minister won the confidence vote with a majority of 83, with 63% of Conservative MPs backing her and 37% voting against her.
The secret ballot was triggered by 48 of her MPs angry at her Brexit policy, which they say betrays the 2016 referendum result.
Speaking shortly after the result was announced, Mrs May said she would be fighting for changes to her Brexit deal at an EU summit on Thursday.
"I am pleased to have received the backing of my colleagues in tonight's ballot," she said.
"Whilst I am grateful for that support, a significant number of colleagues did cast a vote against me and I have listened to what they said."
She spoke of a "renewed mission - delivering the Brexit people voted for, bringing the country back together and building a country that really works for everyone".
Jacob Rees-Mogg, who led calls for the confidence vote, said losing the support of a third of her MPs was a "terrible result for the prime minister" and called on her to resign.
Brexit-backing Tory MP Mark Francois told the BBC it was "devastating" that more than half of backbenchers not serving in the government had abandoned the prime minister.
"In the cold light of day when people reflect on that number - 117 - it's a massive number, far more than anyone was predicting. I think that will be very sobering for the prime minister. I think she needs to think very carefully about what she does now."
Transport Secretary Chris Grayling conceded there were "lessons" for the prime minister and the party in the result but former cabinet minister Damian Green said it was a "decisive" victory for the prime minister, which should allow her to "move on and get on with the job in hand".
Conservative grandee Nicholas Soames urged Brexiteers to "throw their weight" behind the PM as she sought to address the "grave concerns" many MPs had about aspects of the EU deal.
The result was greeted by cheers and applause from Tory MPs as it was announced by backbench Tory chairman Sir Graham Brady.
The prime minister still faces a battle to get the Brexit deal she agreed with the EU through the UK Parliament, with all opposition parties and, clearly, dozens of her own MPs against it. (BBC)