McLaren will return to full-time IndyCar racing in 2020 in partnership with Arrow Schmidt Peterson Motorsports and Chevrolet.
The British team will be renamed Arrow McLaren Racing SP, entering two Chevrolet-powered cars in next year's championship. No drivers were mentioned.
Former Indianapolis 500 winner Gil de Ferran, the sporting director of McLaren Racing, will lead a dedicated group independent of the Formula One team.
McLaren last competed full-time in the IndyCar championship in 1979.
"This team provides McLaren with the right synergy as a strategic partner for our return to the sport. We believe together we can help each other achieve our mutual ambitions," McLaren Racing CEO Zak Brown said in a statement on Friday.
"We come to IndyCar in full respect of the sport, our competitors, the fans and the task ahead."
McLaren have been mulling a full campaign since their failure to qualify Spaniard Fernando Alonso for this year's Indianapolis 500.
Alonso has targeted Indianapolis as the only race in his way to becoming only the second driver after the late Briton Graham Hill to win the so-called "Triple Crown of Motorsport".
The double Formula One world champion has won the Monaco Grand Prix and Le Mans 24 Hours.
McLaren made a catalogue of errors at Indianapolis this year, from having to scrounge a steering wheel at short notice to missing vital track time because the spare car was the wrong shade of orange and was elsewhere being resprayed.
Brown said after that fiasco that he would make sure he got all the right people in the right places before McLaren's next attempt.
"IndyCar is a natural fit for McLaren, given our legacy and determination to succeed at the top levels of international motorsport," De Ferran said.
"Our ambition, over time, is to consistently compete for wins and championships. We acknowledge the challenge ahead of us but McLaren is committed to this partnership and to supporting the team as a whole."