The siege of Roses or siege of Rosas from 7 November to 5 December 1808 saw an Imperial French corps led by Laurent Gouvion Saint-Cyr invest a Catalan and Spanish garrison commanded by Peter O'Daly. After a siege lasting a month in which the haven and town of Roses was captured and the nearby Trinity Castle invested by over 13,000 French and Italian infantry, artillery and cavalry with heavy siege trains on the hills above, the citadel was surrendered to the Napoleonic forces. Roses (Rosas) is located 43 kilometres (27 mi) northeast of Girona, Catalonia, Spain. The action occurred during the Peninsular War, part of the Napoleonic Wars.

Laurent de Gouvion Saint-Cyr, 1st Marquis of Gouvion-Saint-Cyr was a French military commander in the French Revolutionary and Napoleonic Wars who rose to the rank of Marshal of the Empire. He is regarded as Napoleon's finest commander in defensive warfare.