NATO leaders last met in Brussels at the alliance HQ in 2018 (Picture: NATO TV).
Donald Trump will return to the UK in December for a NATO summit.
It will be Mr Trump's second visit to Britain since his election, having jetted in amid swathes of protest last July.
The annoucement comes after confirmed that President Trump will hold a second summit with the North Korean leader Kim Jong Un next month in Vietnam.
Mr Stoltenberg said: "I am pleased to announce that allies have agreed that the next meeting of NATO heads of state and government will take place in London in December 2019.
"The meeting in London will be an opportunity for allied heads of state and government to address the security challenges we face now and in the future, and to ensure that NATO continues to adapt in order to keep its population of almost one billion people safe."
Prime Minister Theresa May said in a statement: "The UK is one of the founding members of NATO and I am very pleased that the Secretary General has asked us to host a meeting of NATO leaders this year to mark its 70th anniversary.
"The UK has played a central role throughout NATO's history as it has adapted to deal with new and complex threats to our security.
"So as we pay tribute to the service men and women who have worked so hard over so many years to keep us safe, December's meeting is an important opportunity to determine the steps we must now take to modernise the Alliance and ensure its continued success."
Mr Trump has repeatedly railed against NATO as he successfully pressured allies to pledge billions more in defence spending.
As recently as Tuesday in Washington, he said in his State of the Union address that the US had been "treated very unfairly by friends of ours, members of NATO" over a period of years.
The summit was announced as Macedonia came a step closer to becoming the alliance's 30th member when allies signed a key document at a ceremony in Brussels.