 On 18 July 2017, Middlesbrough confirmed that they paid £8.8 million for De Roon, with Atalanta earning another £900,000 after the midfielder played 30 games for the club.On 10 August 2017, De Roon re-signed for Atalanta for an undisclosed fee.He once again cemented himself as a starter under Gian Piero Gasperini, and helped Atalanta finish in a historic 3rd place in the 2018–2019 season, earning them a spot in the 2019–20 UEFA Champions League group stage.