Thiago Silva and Olivier Giroud are to remain at Stamford Bridge for another year.
The head coach’s new deal expires in 2024 after he initially joined on an 18-month deal in January, which included an option to extend.
The Blues have also exercised a 12-month option to extend 36-year-old defender Thiago Silva’s stay at Stamford Bridge into a second season, and revealed they did the same to retain the services of striker Olivier Giroud 34, for another year in April.
Tuchel guided Chelsea to a 1-0 Champions League triumph over Manchester City last month and also finished fourth in the Premier League after replacing Frank Lampard.
He told the club’s official website: “I cannot imagine a better occasion for a contract renewal. I am grateful for the experience and very happy to stay part of the Chelsea family.
“There is far more to come and we are looking forward to our next steps with ambition and much anticipation.”
Chelsea also reached the FA Cup final, losing 1-0 to Leicester, and in Tuchel’s 30 games in charge he won 19 times.
Chelsea director Marina Granovskaia said: “When Thomas joined us in January there was still so much to play for domestically and in Europe. He slotted in seamlessly and immediately became an integral part of the Chelsea family.
“Returning us to the top four in the Premier League was crucial, and we could not be happier with our success in the Champions League which crowned a remarkable season at Chelsea.
“We are obviously extremely pleased therefore to retain Thomas for a further two years, and look forward to more achievements in the coming seasons.”
Vastly experienced former Paris St Germain defender Thiago made 34 appearances and scored two goals in his first campaign at Stamford Bridge, although his involvement in the European final was cut short by injury.
Granovskaia said: “When we brought Thiago Silva in last summer, we knew we were adding a world-class player to the squad.
“Thiago has duly shown everyone at Chelsea his immense quality throughout this season, and he has had a huge influence on and off the pitch for us.
“We said when he signed that we hoped Thiago would add new trophies to his impressive list of honours, and he has done just that with our success in the Champions League this weekend. We now hope that he carries on in exactly the same fashion in the coming year.”
Commenting on Giroud’s extension, Granovskaia added: “Olivier has been such a crucial part of so many big moments for this club, from his contribution to our FA Cup victory in 2018 to scoring 11 goals on the way to winning the Europa League in 2019.
“He has continued to score significant goals, and we will never forget his effort against Atletico Madrid on the way to winning the Champions League this season.
“With so much to still to play for, there was only one decision we could make when we exercised the option to extend his contract back in April.”