At a Downing Street press conference, Boris Johnson said: "We have taken back control of our laws and our destiny."
The prime minister added that although arguments had been "fierce" it was a "good deal for the whole of Europe", driving jobs and prosperity.
EU chief Ursula von der Leyen said it was a "fair and balanced" deal.

CNN host Larry King dead at 87
News of King’s death was posted on his Twitter account Saturday in a statement from Ora Media, his digital TV network.