Earlier in the summer, it looked like Monga, 17, would be heading to Arsenal, but the Premier League champions were unable to agree a fee.
Man City swooped in and got the deal done, signing the young winger from Leicester for a reported £10 million, with a further £2.5 million in performance-related add-ons, signing a five-year deal until 2031.
Monga is the third youngest Premier League player of all time, making his top flight debut against Newcastle at just 15 years and 271 days.
Speaking to the club’s website, Monga said: “When I became aware that Manchester City were interested, I knew instantly this was the right choice for me.
“For any young footballer, to become part of this amazing club is a dream come true.
“This has been the best club in England over the past 10 years. And it has also handed opportunities to players from the Academy like Phil Foden and Nico O’Reilly which shows that the pathway is there.
“It is a privilege to be here and I’m delighted to have joined.”