Girmay became the first African to claim the jersey, the Tour's second most important prize after the leader's yellow jersey, on Sunday after three stage wins during this year's race.
The 24-year-old joined Belgian team Intermarche in 2021 and has also a stage win at the Giro d'Italia and a victory in the one-day Gent-Wevelgem under his belt.
"Intermarche-Wanty is like a family to me, the perfect team to achieve my goals," Girmay said in a team statement on social media.
"In all circumstances, the team supported and trusted me, even during the most difficult times. Extending the adventure for two more years is obvious choice," he added.
Girmay's next race will be the Paris Olympics time trial on Saturday before targeting the Games' road race on August 3.
"I'm convinced that we can still achieve great things together," he said.
"I'm already looking to the next goals, starting with the Olympics!" he added
