The Achterhoek (Dutch pronunciation: [ˈɑxtərɦuk]; Dutch Low Saxon: Achterhook) is a cultural region in the Eastern Netherlands. Its name (meaning "rear-corner") is geographically appropriate because the area lies in the easternmost part of the province of Gelderland and therefore in the east of the Netherlands, protruding into Germany. The Achterhoek lies at the east of the IJssel and Oude IJssel rivers. On the other sides, it borders Germany to the southeast and the province of Overijssel to the northeast.

In 2015, the Achterhoek had a population of 389,682. The region is also called de Graafschap (Dutch for earldom, shire or county; namesake of VBV De Graafschap in Doetinchem) because it coincides with the historical County of Zutphen. The region is predominantly rural, with much open space, forests and farms. The area around the city of Winterswijk is regarded as noteworthy. A well-known beer originates from this region: Grolsch beer was first brewed in Groenlo in 1615.