 In his breakout season with Başakşehir, Ünder established himself as one of the best players in the league, scoring 7 goals in 32 games in his debut season in the Süper Lig.On 16 July 2017, he became a Roma player for a €13.4 million fee.He scored his first goal for Roma in a 1–0 win over Hellas Verona in the Serie A on 4 February 2018.