Pisa Cathedral (Italian: Cattedrale Metropolitana Primaziale di Santa Maria Assunta; Duomo di Pisa) is a medieval Roman Catholic cathedral dedicated to the Assumption of the Virgin Mary, in the Piazza dei Miracoli in Pisa, Italy, the oldest of the three structures in the plaza followed by the Pisa Baptistry and the Campanile known as the Leaning Tower of Pisa. The cathedral is a notable example of Romanesque architecture, in particular the style known as Pisan Romanesque. Consecrated in 1118, it is the seat of the Archbishop of Pisa. Construction began in 1063 and was completed in 1092. Additional enlargements and a new facade were built in the 12th century and the roof was replaced after damage from a fire in 1595.

Construction on the cathedral began in 1063 (1064 according to the Pisan calendar of the time) by the architect Buscheto, and expenses were paid using the spoils received fighting against the Muslims in Sicily in 1063. It includes various stylistic elements: classical, Lombard-Emilian, Byzantine, and Islamic, drawing upon the international presence of Pisan merchants at that time. In the same year, St. Mark's Basilica began its reconstruction in Venice, evidence of a strong rivalry between the two maritime republics to see which could create the most beautiful and luxurious place of worship.