Pierre Gasly and Nyck de Vries will join the all- French line-up at Alpine.
Fernando Alonso left Alpine after they failed to meet his demands for a new contract.
Gasly left Red Bull for the first time in his career after the company agreed to let him go.
He made his full-time Formula 1 debut.
He said he was "delighted to begin this new chapter in my life".
It is very special to drive for a team that has French roots. Alpine has been racing against them over the past couple of years and their progress and ambition is very impressive.
Gasly and Ocon are the first French drivers in 20 years.
They have a long history. They were childhood friends in karts but fell out. Four years ago, Gasly said, "We're not friends anymore because he didn't like it when I beat him."
Alpine talked to Ocon before committing to Gasly, according to the team principal.
Pierre andEsteban were very supportive. They are professional. They have no problem with us working together. At one time, they were friends. They are both very happy to work with each other.
De Vries, the champion of the all-electric Formula E series and Mercedes reserve driver, emerged as a candidate for Red Bull's sister team after their attempts to recruit her failed
The American, who has tested for McLaren this season, does not qualify for an F1 driver super-licence and the governing body of the sport refused to allow him an exception.
As a stand-in for Alex Albon at the Italian Grand Prix, De Vries convinced Red Bull that he was the right driver to replace Gasly.
The Formula 2 champion stepped in at the last moment when the British-born Thai was in the hospital.
F1 has always been my dream and I'm grateful to be able to fulfill it after taking a different path with motor sport.
I've had a lot of chances to experience the car this year and I think that has put me in a good position for the upcoming season, I hope this has helped to prepare me for what is to come.
Last month, he was confirmed to continue with Alpha Tauri.