The Ecuadorian, who has penned a three-year deal, will joust for leadership duties with Chris Froome, Geraint Thomas and Egan Bernal.
“I am very excited about joining the team. I feel this is a great opportunity for me to continue my development and growth as a rider, working with a team that continues to go from strength-to-strength, year after year,” said Carapaz.
“I already know a lot of the riders on the team and I am really looking forward to working everyone at Team INEOS from next season.”
“I believe I will fit into this group well and race to my full potential over the coming years. I want to achieve some great triumphs for Team INEOS.”
Carapaz withdrew ahead of La Vuelta after sustaining multiple injuries in a crash in the build-up, with the 26-year-old returning to action at the Bretagne Classic on Sunday.
“We are very pleased to have signed Richard from the start of the 2020 season,” added Ineos team principal Dave Brailsford.
“We have been long time admirers of his talents as a bike rider and have followed his development closely over a number of years, as we have always marked him out as a potential member of our Team.”
“He is obviously a fantastic climber but also has great versatility as he showed at the Giro earlier this year. He is still relatively young and I have no doubt he can develop and improve even further at Team INEOS.”
Bernal led home Thomas in an Ineos one-two at the Tour de France in July, while Froome began the slow road to recovery following his horror crash in June.