One Grand Summer (German: Der große Sommer) is a 2021 coming-of-age novel by German author Ewald Arenz. Set in the 1980s in West Germany, the story follows 16-year-old Frieder Büchner as he spends a transformative summer with his grandparents, with themes of first love, friendship, and family relationships. It became a bestseller in Germany and has been translated into several languages.