She said Britain needed certainty, stability and strong leadership following the EU referendum.
Justifying the decision, May said: “The country is coming together but Westminster is not,” reports the BBC.
There will be a Commons vote on the proposed election on Wednesday – she will need Parliament’s backing to hold a vote before 2020.
Explaining her change of heart on an early election, May said: “I have concluded the only way to guarantee certainty and security for years ahead is to hold this election.”
May accused the other political parties of “game playing”, adding that this risks “our ability to make a success of Brexit and it will cause damaging uncertainty and instability to the country”.
“So we need a general election and we need one now. We have at this moment a one off chance to get this done.”