Ordoño II (أردون بن إذفنش (Urdūn ibn Iḍfunš)) (c. 873–924, León) was king of Galicia from 910 and king of Galicia and León from 914 until his death. He was the second son of the King Alfonso III the Great and his wife, Jimena of Navarre.
His father sent him to Zaragoza to be educated in the court of the Banu Qasi. Upon Alfonso's death in 910, his sons divided the kingdom. León went to García, Galicia to Ordoño, and Asturias to Fruela. Asturian primacy was nevertheless recognised, though Ordoño was of a harder temperament than his brothers. Upon his brother García's death in Zamora in 914, he succeeded him in León.
Ordoño continued thereafter the expansion of the Christian polity of his forefathers on two fronts. In the west of his territiories, he sacked Mérida and Évora and forced the Muslim governor of the region to buy his retreat.
In the east of his territories, he united with Sancho I Garcés, king of Navarre, against the emir of Córdoba, Abd-ar-Rahman III. The Moors were destroyed at San Esteban de Gormaz (917). Arnedo and Calahorra were taken the next year from the Banu Qasi. The reaction of Abd-ar-rahman, however, was not light. In 920, he put to march and army to recover Osma and San Esteban de Gormaz. He crossed into Navarre and destroyed the Christians at Valdejunquera and took captive the bishops of Tui and Salamanca. Though intending to crush Pamplona itself, he turned around to deal with his immense booty.
Ordoño II—who had come at King Sancho's request—attributed the loss to the absence of the counts of Castile, who had not come at his call. He brought them together at Tejares and had them killed. The Christian counteroffensive was immediate, occupying La Rioja and incorporating into Navarre Nájera and Viguera.
Ordoño married three times. His first wife and the mother of his children was Elvira Menendez, daughter of count Hermengildo Gutierrez. He them married Aragonta Gonzalez, daughter of count Gonzalo Betotez. He set her aside because she was not pleasing to him, and when he formed a political alliance with Sancho I of Pamplona, he was married to that king's daughter, Sancha. He died in 924 leaving young children, and was succeeded by his eldest surviving brother, Fruela, the king of Asturias, thereby reuniting their father's patrimony.