Sancho Garcés, Lord of Uncastillo

Sancho Garcés (c. 1038 – 1083) was an illegitimate son of King García Sánchez III of Pamplona, born before his father married Queen Stephanie. He held the lordships of Uncastillo and Sangüesa.

Before 1057 he married Constanza; their son Ramiro Sánchez, lord of Monzón, married a daughter of El Cid and fathered García Ramírez the Restorer, founder of a new Navarrese dynasty. Sancho was killed in 1083 at the treachery of Rueda, stoned with his half-brother Ramiro after entering the surrendered Muslim castle.