The mythology of modern-day Netherlands, Belgium and Luxembourg have their roots in the mythologies of pre-Christian (e.g. Gaulish (Gallo-Roman) and Germanic) cultures, predating the region's Christianization by the Franks in the Early Middle Ages.
In the time of the Roman Empire and Early Middle Ages, the Low Countries' resident peoples included: Germanic tribes north of the Rhine River (with a lot of exceptions Like the Eburonsor Nervii,...) (Low Franconians, Frisians, Tubanti, Canninefates, Batavians), as well as the decidedly more Celtic and Gallo-Roman Belgae tribes of Gallia Belgica south of the Rhine (also mainly but with many exceptions).Old Dutch mythology can also mean the myths told in Old Dutch language specifically, however many of the myths in this language are ancient and part of larger movements across Europe, such as Roman mythology that spread through the Roman Empire, and Continental Germanic mythology.
Pre-Christian traditions of veneration of trees (particularly the oak, see Donar's oak), springs and woods native to the Low Countries survived in Christianized guise into the Middle Ages.