Real Sociedad have announced that Isak has signed a new contract with the club until June 2029.
The Swedish striker, who joined the La Liga side in 2018 from Malmo FF, has made 64 appearances for the team and scored 27 goals in all competitions.
"Isak is one of the best strikers in the world," said manager Arteta after the news was confirmed.
"He brings so much quality to our team and we're delighted to have him here until 2029."
The deal means that Isak will remain at the club for another seven years, although he can leave on a free transfer after that time if he chooses to do so.
"I'm really happy to be staying at Real Sociedad," said Isak.
"This is a fantastic club with great fans and I'm looking forward to continuing my career here."
The signing of Isak marks the latest addition to the squad ahead of next season's campaign.
With several key players set to depart, it is likely that the team will be in for a busy summer as they look to strengthen their squad further.
However, Isak's new contract should provide some much-needed stability for the squad, as they look to compete for honours once again next season.