Nuestra Señora de las Mercedes (Our Lady of Mercy in English, a title of the Virgin Mary) was a Spanish Navy frigate which was sunk by the British off the south coast of Portugal on 5 October 1804 during the Battle of Cape Santa Maria.

The Spanish frigate was part of a small flotilla sailing from Montevideo (Uruguay) to Cadiz (Andalusia, Spain), transporting silver, gold, vicuña, cinnamon, and quinoa.

The flotilla was intercepted by a Royal Navy task force, commanded by Graham Moore aboard HMS Indefatigable, and ordered to change course and proceed to a British port for inspection.

Her wreck has been compared with that of USS Arizona at Pearl Harbor, due to the loss of life and the unprovoked attack leading to war between Spain and Britain.

[citation needed] On 2 December 2012 the 14.5 tons cargo of gold and silver coins recovered from the wreck was deposited in the National Museum of Subaquatic Archaeology in Cartagena (Murcia) for cataloging, study and permanent display.