The Castle of Montemor-o-Velho (Portuguese: Castelo de Montemor-o-Velho) is a Portuguese castle in the civil parish of Montemor-o-Velho e Gatões, municipality of Montemor-o-Velho, district of Coimbra.
It has been listed as a national monument since 1910. It is older than Portugal's nationality (1139).
Since 2014, the castle hosts the Festival Forte which is an electronic music festival set in August.
40°10′34″N 8°40′59″W / 40.176°N 8.683°W / 40.176; -8.683