Here is Mrs May's full statement made outside 10 Downing Street at 11am this morning.
"I have just chaired a meeting of the Cabinet, where we agreed that the Government should call a general election, to be held on June 8.
"I want to explain the reasons for that decision, what will happen next and the choice facing the British people when you come to vote in this election.
"Last summer, after the country voted to leave the European Union, Britain needed certainty, stability and strong leadership, and since I became prime minister the Government has delivered precisely that.
"Despite predictions of immediate financial and economic danger, since the referendum we have seen consumer confidence remain high, record numbers of jobs, and economic growth that has exceeded all expectations.
"We have also delivered on the mandate that we were handed by the referendum result.
"Britain is leaving the European Union and there can be no turning back.
"And as we look to the future, the Government has the right plan for negotiating our new relationship with Europe.
"We want a deep and special partnership between a strong and successful European Union and a United Kingdom that is free to chart its own way in the world.
"That means we will regain control of our own money, our own laws and our own borders and we will be free to strike trade deals with old friends and new partners all around the world.
"This is the right approach, and it is in the national interest. But the other political parties oppose it.
"At this moment of enormous national significance there should be unity here in Westminster, but instead there is division.
"The country is coming together, but Westminster is not.
"In recent weeks Labour has threatened to vote against the deal we reach with the European Union.
"The Liberal Democrats have said they want to grind the business of government to a standstill.
"The Scottish National Party say they will vote against the legislation that formally repeals Britain's membership of the European Union.
"And unelected members of the House of Lords have vowed to fight us every step of the way.
"Our opponents believe that because the Government's majority is so small, our resolve will weaken and that they can force us to change course.
"They are wrong.
"They under-estimate our determination to get the job done and I am not prepared to let them endanger the security of millions of working people across the country."
The Fixed-Term Parliaments Act means the snap general election can only happen if two-thirds of MPs vote for it in the Commons. The vote is due to be held tomorrow.