Albon's previous Williams contract was due to end in 2025, but his excellent 2023 form for the Grove team made him a left-field player in next year's driver market.
But the 28-year-old has now pledged his future to Williams for 2026 and beyond, with the team announcing it has re-signed him on what has been called a "multi-year" deal.
"I am incredibly happy to be remaining with Williams Racing and to continue working with such a talented and dedicated team of people,” Albon said.
“It has been a difficult start to the year but since joining Williams we have made significant progress together and I have seen the huge changes happening behind the scenes to take us back to the front of the grid.
“This is a long-term project that I really believe in and want to play a key role in which is why I have signed a multi-year contract.
“The journey will take time but I am confident we are building the right team to move forward and achieve great things in the years to come.”
Team boss James Vowles said he was pleased to secure his lead driver for the foreseeable future as he continues to put the building blocks in place for Williams to return to the front of the field.
"We are delighted to secure Alex's long-term future with Williams Racing," said Vowles.
“He has exceptional talent, technical input and dedication to the cause and this is a huge vote of confidence in Williams and the journey back to competitiveness that we are on.
“Since joining, Alex has consistently demonstrated his ability to perform under pressure, and signing him for the long-term is a big piece of the puzzle of moving us up the grid."
Having taken a year out of the series when he lost his Red Bull race seat, Albon joined Williams in 2022.
He quickly established himself as the team's lead driver and in 2023, he single-handedly dragged the struggling Williams up to seventh place in the constructors' championship by scoring 27 of the team's 28 points.
Albon and his team are yet to score points in 2024 after a difficult start to the year, with the squad desperate for upgrades in a tight midfield battle.
Speaking after another non-score in Miami, Albon underlined his belief in Vowles' ambitious long-term plans to turn the team around.
"It's true that we haven't started the year where we wanted to," Albon said. "We've not had the pace and we've been a bit delayed on our updates and upgrades.
"I do believe the team is strong and healthy. I feel like there is definitely going to be an improvement. It's always nice if it happens now, but James is the right person for the job. There is definite progress."
