On 31 August 2017, Rebić joined Eintracht a second time on loan for another year with an option to buy. Across all competitions, he scored nine goals and assisted three that season. This included two goals on 19 May in the 2018 DFB-Pokal Final, a 3–1 victory that gave his club their first cup since 1988 and denied Bayern Munich to complete their double. At the conclusion of the season, Eintracht Frankfurt exercised their option to purchase Rebić permanently for €2 million.