Castle of Penela (Portuguese: Castelo de Penela) is located in a town of the same name in Coimbra region, Portugal. The castle was built on a hill dominating the area and used to be a stronghold protecting Coimbra in times of Reconquista. Castle of Penela and the neighboring castle Montemor-o-Velho are both fine examples of defensive structures of that period.

The origins of the name are controversial and are attributed by some authors to ancient Celtic tribes. According to a local legend, King Afonso I (Afonso Henriques) exclaimed to incite his troops storming the stronghold: Coragem! Já estamos com o pé nela! (Courage! We have already set a foot in it!). A more plausible hypothesis is, however, that penela is a diminutive of penha, a place selected to build a fortress on.