Bernat Guillem d'Entença, (Spanish:Bernardo Guillermo de Entenza), (b. ? - d. El Puig, 1237) was a Spanish noble of the Catalan-Aragonese House of Entença. He was the señor of Fraga. He was best known for his participation in the Spanish Reconquista in the campaign for control over Valencia (Balensiya), culminating with his victory over Zayyan ibn Mardanish at the Battle of the Puig where he died.
Bernat was a member of the House of Entença. He was the son of Bernat Guillem d'Montpeller Entença and Jusiana de Entenza who were the respective uncle and aunt of James I of Aragon.
In July 1215, he received the señorío of Fraga, together with the possession of other castles ceded by his brother, Guillem d'Entença. Previously, parts of Fraga were shared with the Count of Urgell and the Viscount of Béarn. The king returned rent money that had gone to Urgel back to Fraga and Entença in 1215.
He participated with James I of Aragon in the conquests of Mallorca and Valencia. He commanded the king's forces at the Siege of Burriana where he was injured. He died in camp at the Battle of the Puig from wounds received in battle. He was also the general commander of the forces of the Kingdom of Aragon at El Puig.