The former Prime Minister received 32,620 votes in Maidenhead as the Liberal Democrats beat Labour to second place.
The Lib Dems received a 10.1% swing from the Tories compared with the 2017 election.
Labour held the marginal seat of Reading East with an increased majority while the Conservatives kept Reading West.
In Maidenhead Mrs May polled ahead of the Liberal Democrats Joshua Reynolds by 18,846 votes, 7,611 less than the majority in 2017.
She said: "At this election people were faced with a very clear choice about whether or not they wanted to ensure that Brexit was delivered and they knew that if a Conservative majority government got in that we would deliver Brexit."
Result in Maidenhead
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Matt Rodda, who took Reading East from the Tories in 2017, saw off the competition from former MP Craig Morley to increase his majority to 5,924 in the heavily Remain-voting constituency.
He said the scale of victory was "really surprising" and his campaign had "done better than expected".
Tory MP Alok Sharma held on to marginal Reading West increasing his majority to 4,117 votes.
Previously Mr Sharma, who has held the seat since 2010, narrowly held onto the seat from Labour in 2017 with a majority of 2,876.
"It's really quite humbling to be re-elected for a fourth time," he said.
Elsewhere in Berkshire, Wokingham MP John Redwood held onto his seat but with a significant drop in his majority.
Mr Redwood polled 7,383 votes ahead of the Liberal Democrat Phillip Lee, a decrease in his majority from 18,798 in 2017.
In Newbury, Conservative Laura Farris beat Liberal Democrat Lee Dillon by 16,047 votes.
She takes over from former Tory MP Richard Benyon who decided to step down at this election.
James Sunderland has been elected MP for Bracknell, meaning that the Conservative Party holds the seat with an increased majority.
The new MP beat Labour's Paul Bidwell by 19,829 votes. This was more than Phillip Lee's 16,016 vote majority in the 2017 general election.
Conservative Adam Afriyie held Windsor beating Julian Tisi by 20,079 votes.
In Slough, Tan Dhesi held his seat beating Conservative Kanwal Toor Gill by 13,640 votes, 3,358 less than than majority at the 2017 election.
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https://www.bbc.com/news/election-2019-50772311
