The Nigeria international initially joined from Brentford on loan in January, with the deal including an obligation to make the transfer permanent.
Onyeka quickly became an important player, making 14 Championship appearances and scoring once.
He is now excited to continue his journey with Frank Lampard’s side as Coventry prepare for life in the Premier League.
“It’s really nice. From the first day I came in, I felt the beauty of the people and the club. I just felt, this is for me, I’m in the right place to be,” Onyeka told Coventry Telegraph.
“All the boys, the people around the building made me feel really comfortable and I settled in quickly which is really nice for every player that goes into a new team.
“I felt really, really happy and now I’ve been here on the last five or six months and feel really comfortable.
“The love I got from the fans from the first day was really lovely to see how they took me in, how they loved me, and I really appreciate that.”