Ciudad Vieja (Spanish pronunciation: [θjuˈðað ˈβjexa], Old City) is a historic neighbourhood in Montevideo, the capital of Uruguay. Located in a peninsula at the entrance of the natural port of Montevideo it was founded in 1724 as a walled city by the Spanish Empire, after the independence of Uruguay the city rapidly grew outwards and the Ciudad Vieja remained as one of the central neighbourhoods, nowadays it serves as one of the main office districts of Montevideo, housing multiple banks and institutions, but also as one of main tourist attractions in Uruguay due to its historical significance and classical architecture.

Until 1829 it was surrounded by a wall that protected it from possible invasions. After the wall was torn down, the only part of it that was preserved was the main gateway to the Citadel, which remains to this day as an emblem of Montevideo. Some street names recall the presence of the wall, like Ciudadela (citadel) or Brecha (breach), which owns its name to the breach in the wall that the British managed to open to enter the city during the 1807 British invasion and brief occupation of the city before they were defeated.