The former Chelsea and Bayern Munich coach has been appointed to June 2026.
Tuchel will take charge from January 1, with caretaker coach Lee Carsley remaining in charge for the final two ties of the Nations League in November.
Tuchel said, "I am very proud to have been given the honour of leading the England team.
"I have long felt a personal connection to the game in this country, and it has given me some incredible moments already.
"To have the chance to represent England is a huge privilege, and the opportunity to work with this special and talented group of players is very exciting."
Chief executive Mark Bullingham said the Football Association had appointed "one of the best coaches in the world".
He said: "Thomas and the team have a single-minded focus on giving us the best possible chance to win the World Cup in 2026."