The Santa Cruz Monastery, (English: Holy Cross Monastery, Portuguese: Mosteiro de Santa Cruz, best known as Igreja (Church) de Santa Cruz) is a National Monument in Coimbra, Portugal. Founded in 1131 outside the protecting walls of Coimbra, the Santa Cruz Monastery was the most important monastic house of the first times of the Portuguese monarchy. Dedicated to the Order of St. Augustine, the Monastery was granted numerous papal privileges and royal grants, which allowed the accumulation of a considerable patrimony, at the same time as it consolidated its position on the politico-institutional and cultural scene. Its school was essential on medieval times and also a meeting point for the intellectual and power elites. Its scriptorium was responsible for the propaganda machine of King Afonso Henriques, being not strange at all his decision to be buried exactly in Santa Cruz of Coimbra.

Nothing remains of the early Romanesque Monastery. It is known that it had only one nave and a high tower in the façade, as typical of the Augustine-Romanesque constructions, but none of those elements subsisted. In the first half of the 16th century, the Monastery was completely reformed by King Manuel's order, this monarch having assumed the Monastery tutelage.

The whole monastic ensemble, the church and the tombs of King Afonso Henriques and of his successor, King Sancho I, were rearranged and transferred to the main-chapel in 1530, where they still lie in a sculptural work by Nicolau Chanterene. The architect Diogo Boitac was responsible for the layout of the Manueline church and the Chapter House with its basket-handled and ribbed ceilings. Marco Pires gave continuity to the work, with the completion of the church, the Capela de São Miguel (St. Michael's Chapel) and the Claustro do Silêncio (Cloister of Silence). The main portal, made between 1522 and 1525 under Chanterene, is the most emblematic piece of the whole monastic ensemble, harmonising the artistic elements of the Manueline with other features from Renaissance inspiration.