 In November 2016 Ünder received his first call-up to the senior Turkey squad for the match against Kosovo.He scored his first international goal in his second cap for his country in a friendly victory against Moldova in March 2017.Following the Afrin offensive in Northern Syria, which as carried out by the Turkish Armed Forces in January 2018, on 11 February, Ünder performed a military salute as a goal celebration after netting in Roma's 5–2 home win over Benevento in Serie A.