The Battle of Graus (or Siege of Graus) was a battle of the early Spanish Reconquista in spring 1063 (some sources say the battle was in early May, possibly around May 8). The engagement took place in Graus and was fought between the Aragonese forces of Ramiro I and the Moorish forces of al-Muktadir, the king of Zaragoza. A Castilian contiginent under then-Prince Sancho was allied with Al-Muktadir and also took part in the battle. Sancho later became King Sancho II.

During the battle, Ramiro was killed. The engagement was also the first combat experience of El Cid, who fought with the Castilians. The Cid was around 20 years old at the time.