The Battle at the Harzhorn takes place in the early 3rd century between Germanic and Roman troops near the Harzhorn hill between the towns of Kalefeld and Bad Gandersheim, in the state of Lower Saxony, Germany.The battlefield, spanning several square kilometers, was discovered in December 2008 and is currently being excavated.

Roman coinage found at the site gives a probable date of the battle to the reigns of Roman emperors Severus Alexander (222 to 235), or Maximinus Thrax (235 to 238).Archaeologists view the battlefield as a spectacular discovery of extraordinary scientific importance.

Along with the Kalkriese battlefield and the Roman camps Bentumersiel and Hedemünden, this is one of the very few Roman archaeological sites in Northern Germany.