"When I heard that Manchester City were interested, I knew straight away that it was my choice. It's every young footballer's dream to be part of the club," Monga told Manchester City's website.
Monga made his Premier League debut at the age of 15, becoming the second youngest player to debut in the English top division.
When Leicester were relegated from the Championship to League One this spring, it became clear that the highly rated talent would change clubs.
