The 52-year-old said after last week's defeat to defending champions France in Qatar that he would take his time before making a decision over his future.
But he is now set to stay at the helm until after the 2024 European Championship.
"We are delighted to confirm that Gareth Southgate is continuing as England manager and will lead our Euro 2024 campaign," said FA chief executive Mark Bullingham.
"Gareth and (assistant coach) Steve Holland have always had our full support and our planning for the Euros starts now."
England have not won a major trophy since their World Cup victory in 1966 but under Southgate they reached the semi-finals of the 2018 tournament and the final of last year's European Championship.
His current deal runs until December 2024.
England's latest bid to end their long wait for a major trophy ended in last Saturday's 2-1 defeat to France, who went on to reach the final against Argentina.
Harry Kane blazed over from the penalty spot when handed a chance to equalise late in the game, having earlier scored from the spot.
England's first Euro 2024 qualifier is against Italy on March 23. Ukraine, North Macedonia and Malta are also in the same group.
Check the 2022 World Cup matches and statistics.
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