Daniel Ricciardo (left) is five places behind team-mate Lando Norris in this season's championship
The team said they and the Australian had "mutually agreed" the split, but McLaren admitted they had precipitated the move.
The announcement is expected to be followed by confirmation that McLaren have signed Australian Oscar Piastri - the Formula 2 champion and Alpine reserve.
McLaren said they would confirm their 2023 driver line-up "in due course".
The team already have Lando Norris under contract until the end of 2025.
McLaren have decided to terminate Ricciardo's contract a year early after what they considered unsatisfactory performances from the eight-time winner.
On average, Ricciardo has been 0.356 seconds slower than Norris in qualifying this season, and has qualified three places lower.
Norris is five places higher in the championship, seventh compared to 12th, having scored 76 points to Ricciardo's 19.
Ricciardo did win a race for McLaren, at last year's Italian Grand Prix, but on balance he lagged behind Norris in 2021 as well.
McLaren team principal Andreas Seidl said: "There was a contract and it needed mutual agreement to terminate it early, but after discussion with Daniel we felt it was the right thing for both sides to split ways for next year."
He added: "If you look back at the last 18 months of our journey together, Daniel and McLaren, it's clear we haven't achieved the result we wanted, despite highlights like the great win in Monza last year.
"That's why we had a lot of discussions but in the end we had to acknowledge we did not make it work together despite the commitment that was there from Daniel's side and all the effort the team has put in and that's why we came to the agreement we would terminate the contract at the end of this year.
"It's not the outcome we wanted but we want to put in all the effort to finish the relationship on a high."
Daniel Ricciardo's sole race win for McLaren came in Monza in September 2021
Ricciardo said in a McLaren statement that he would announce his plans in due course. McLaren Racing chief executive officer Zak Brown said the 33-year-old wanted to continue in F1.
Ricciardo added: "Regardless of what this next chapter brings, I have no regrets and am proud of the effort and work I gave McLaren, especially the win in Monza, last season.
"I've enjoyed working with everyone at McLaren both trackside and back in Woking [at the factory] and will be giving my all on and off track as we enjoy the remainder of the season together.
"I've never been more motivated to compete and be a part of a sport that I love so much and look forward to what comes next."
Seidl and Brown both said they had been "surprised" they had not been able to make it work with Ricciardo, and Seidl said it was "unfortunate we have ended up in this position".
Seidl added: "He said it himself - we simply didn't manage as a team to make him feel fully comfortable in the car, especially when it came to going to the absolute limit in qualifying.
"We tried a lot but unfortunately we didn't make it work.
"For an F1 driver, pulling off performance, he needs to be fully one with the car. If you remember all the comments Daniel made about the challenges, we simply didn't manage to get him as comfortable with the car as Lando was.
"We put in a lot of effort and commitment to help him; he put in a lot of effort as well. But we still didn't manage to unlock these percentages that were missing."
-- Courtesy of BBC Sport