Lawmakers in the House of Commons voted 522 to 13 on Wednesday to support the motion put forward by May a day earlier.
The election will be held on June 8, nearly a year after 52 percent of Britons voted to leave the European Union (EU).
The parliament will dissolve on June 3.
On Tuesday, May made a unexpected announcement that she would seek a "snap" election less than halfway through her government's five-year term, with the goal of gaining a stronger mandate for Britain's withdrawal from the European Union.
She said holding an election as previously scheduled in 2020 will not give the UK "certainty and stability" as it negotiates its exit from the EU.
May said an early election will bolster the UK’s position in talks over Brexit and is in the country’s national interest.
“I want this country to be able to play the strongest hand possible in those negotiations to get the best possible deal because that’s in our long-term interests,” she said.
“That’s what this is about, it’s about asking the people to trust me, to trust us in government, to give us that mandate to go and get that really good deal for the UK.”
May’s call for an early election came after firm assurances that she would not seek a new election before 2020. She had resisted calls for an early election from within her own party for months.
The latest polls predict an easy win for May. The premier has already backed out from televised debates.
During Wednesday’s weekly session of Prime Minister's Questions in the House of Commons, Jeremy Corbyn, the leader of the main opposition Labour Party, urged May to take part in a televised debate ahead of the election, but May maintained she had no interest in doing so.
Unlike May, her predecessor David Cameron took part in high-profile election debates in 2010 and 2015. Cameron stepped down after the Brexit referendum.
During the Prime Minister's Questions, May accused opposition lawmakers of trying to sabotage the Brexit process.
"What the British people -- what the people of the United Kingdom -- voted for last year was for the UK to leave the European Union. We have set that process in motion, there is no turning back.”
The European Commission says Brexit talks will be held in June after the elections in Britain. London triggered article 50 of the Lisbon treaty on March 29 to formally start negotiations on leaving the EU.