Sancho Sánchez (fl. 1075–1127) was an important magnate of the Kingdom of Aragon in the late 11th and early 12th centuries, during the reigns of Sancho Ramírez, Peter I and Alfonso I. He was governor of the important Navarrese tenancies of Erro (from 1080), the castle of San Esteban de Deyo (1084), the capital city of Pamplona (1092), Aibar and Tafalla (1098) and Falces and Leguín (1112). In Aragon proper, he governed the important fortress of El Castellar overlooking Muslim Zaragoza from 1091 and the town of Ejea from 1113. He held the rank of count (Latin comes) from 1085, before that he was a lord (senior).
According to the Historia Roderici, he was captured in the battle of Morella on 14 August 1084 by the forces of Yusuf al-Mu'taman ibn Hud, king of Zaragoza, and Rodrigo Díaz de Vivar.
Between 1087 and 1113 he was responsible for the County of Navarre, the interior of the old Kingdom of Pamplona which had passed to King Sancho upon Pamplona's division in 1076. Nonetheless, Sancho Ramírez had done homage for Navarre to King Alfonso VI of Castile and so Sancho Sánchez acted in fact as Alfonso's vassal in Navarre. The latter is never referred to as Count of Navarre in royal documents, but only in documents of local origin. This is perhaps a sign that the status of Navarre proper between Aragon and Castile was not completely settled.