Fortaleza de Sagres ("Sagres Fortress") is a military fortification from the 15th century, located in the extreme Southwest of Portugal, in the Algarve region.

It is directly linked to the period of Portuguese maritime exploration and to the role Infante D. Henrique played in investing in the training of Portuguese sailors and the development of related technologies at the time.

Fortaleza de Sagres is the most visited historic monument in the Algarve region.