Diego Peláez was an eleventh-century bishop of Santiago de Compostela and a prominent figure in the Galician ecclesiastical nobility.
Peláez was named bishop shortly after García, king of Galicia, was imprisoned by his brother Sancho II of Castile.
It appears that Peláez was involved in the uprising of the Galician noble Rodrigo Ovéquiz, which Alfonso VI spent two years putting down, and which he attempted to resolve by splitting the Kingdom of Galicia into two feudal territories.
The land north of the river Miño was given to his daughter Urraca (totia Gallecie Imperatrix) and her husband, Raymond of Burgundy.
The land south of the river was given to his illegitimate daughter Teresa and her husband Enrique de Borgoña, creating the second County of Portugal.
He escaped his imprisonment in 1094 and took refuge in the kingdom of Aragón;[3] the same year, the Cluniac Dalmacio was named bishop of Iria and Santiago de Compostela.