The 25-year-old has penned a three-year deal with the option of a further year for a reported fee of £2.1million.
Robins manager Steve Cotterill said: "We're very pleased Jonathan has decided to join us because there has been lots of interest in him in the past year.
"He's a good age, has great pace, has scored some fantastic goals, and more importantly will fit into the young group we already have. We've kept an eye on him for the last 12 months, so it's great we've been able to get him on board.
"When you look at the striker market out there now some of the prices quoted are completely out of our reach and unrealistic, so to get Jonathan at the price we have we feel is good business
"Attack is an area we're light in, especially with the injury to Kieran Agard, so now we have signed another striker that allows us to concentrate on strengthening other areas of the team."
NEWS: Jonathan Kodjia becomes #BristolCity's first summer signing. http://t.co/J5NeuxLyCRpic.twitter.com/dIrpfntxMp
— Bristol City FC (@bcfctweets) July 20, 2015