Santos-o-Velho is a former freguesia (civil parish) of Lisbon, Portugal, with an area of 0.51 km² and 4,013 inhabitants (2001). It has a population density of 7899.6 inhabitants/km². At the administrative reorganization of Lisbon on 8 December 2012 it became part of the parish Estrela.
It is one of the best preserved historical parts of Lisbon, including Madragoa (former village in the outskirts of Central Lisbon), the Museum of Ancient Art, and many former convents and palaces (in which the current Embassy of France in included).
It is also known for its lively nightlife.