The striker, who played in Inter's Champions League final defeat to Manchester City earlier this month, has signed a two-year deal with the Istanbul-based club. His contract with Inter expires on June 30.
Dzeko scored 31 goals in 101 games after joining Inter from AS Roma in 2021, winning two Coppa Italia and Italian Super Cup titles. He won Premier League and Bundesliga titles with Man City and Wolfsburg and has scored more than 300 goals in his club career.
The Bosnia and Herzegovina international is also the top scorer for his country with 64 goals in 129 appearances.
"Goodbye Inter, it's been two wonderful years," Dzeko wrote on Instagram.
"It has been an amazing journey. We're parting ways now, but thank you for everything."
Fenerbahce finished runners-up to Galatasaray in last season's Super Lig. They last won the league title in 2014.
