England lost 2-1 to Spain in Sunday's showpiece in Berlin and the 53-year-oldEnglishman said after the game that he would discuss his future in charge of the national team.
"As a proud Englishman, it has been the honour of my life to play for England and to manage England. It has meant everything to me, and I have given it my all," Southgate said in a statement.
"But it's time for change and for a new chapter. Sunday's final in Berlin against Spain was my final game as England manager.
"I have had the privilege of leading a large group of players in 102 games. Every one of them has been proud to wear the three lions on their shirts, and they have been a credit to their country in so many ways."
Britain's Prince William, who is also the president of the FA, thanked Southgate for his service.
"Thank you for creating a team that stands shoulder to shoulder with the world's finest in 2024," he said.
"Thank you for showing humility, compassion, and true leadership under the most intense pressure and scrutiny. And thank you for being an all-round class act.
"You should be incredibly proud of what you've achieved."
FROM YOUTH TO SENIOR TEAM
Having coached the England youth side for several years, Southgate took the senior job when Sam Allardyce resigned after one match in charge when he sought a lucrative sideline role while talking to undercover reporters.
A former international with 57 caps, Southgate took over an England side that had seen its "golden generation" of players fail to impress at major tournaments.
With a young core of players, Southgate's England captured the imagination of a country starved of success on the international stage as they became a force to reckon with in tournaments.
England reached the 2018 World Cup semi-finals while their run to the final at Euro 2020 was also remarkable.
With most of their games being played on home soil, the country began to dream of lifting their first trophy since the 1966 World Cup.
But that dream was shattered at Wembley when Italy beat England on penalties while Southgate's side crashed out of the quarter-finals at World Cup the following year in Qatar.
Although they reached the Euro 2024 final, the road to Berlin was not easy as England struggled to find the net and topped the group after scoring just two goals.
Furious supporters hurled beer cups and insults at Southgate and as his team selection was also questioned, he implored the fans to get behind the squad.
Although they beat Switzerland on penalties and the Netherlands with a last-gasp goal, getting the better of Spain proved to be a step too far and Southgate was gracious in defeat, saying the Iberian side were deserved champions.
KNOCKOUT RECORD
However, Southgate's record of taking his teams deep into tournaments is unrivalled among England's other managers.
FA CEO Mark Bullingham said England would be "forever grateful" to Southgate and his assistant Steve Holland for everything they had achieved.
"In the 25 tournaments post 1966 before Gareth took charge, we had won seven knockout games," Bullingham said.
"In his four tournaments we have won nine. So, in his eight years, he has won more games that really matter than in the previous 50 years.
"Before Gareth, our longest time ranked in the top five in the world was seven months. In his tenure we have been ranked there for six years."
Bullingham said the search for a successor is under way and the FA have an "interim solution" in place if they do not find a permanent replacement before their Nations League campaign kicks off in September.
