Chartres Cathedral, also known as the Cathedral of Our Lady of Chartres (French: Cathédrale Notre-Dame de Chartres), is a Catholic church in Chartres, France, about 80 km (50 miles) southwest of Paris, and is the seat of the Bishop of Chartres. Long renowned as "one of the most beautiful and historically significant cathedrals in all of Europe," it was designated a World Heritage Site by UNESCO in 1979, which called it "the high point of French Gothic art" and a "masterpiece".

Mostly constructed between 1194 and 1220, it stands on the site of at least five cathedrals that have occupied the site since the Diocese of Chartres was formed as an episcopal see in the 4th century. It is one of the best-known and most influential examples of High Gothic and Classic Gothic architecture, It stands on Romanesque basements, while its north spire is more recent (1507–1513) and is built in the more ornate Flamboyant style.

The cathedral is well-preserved and well-restored: the majority of the original stained glass windows survive intact, while the architecture has seen only minor changes since the early 13th century. The building's exterior is dominated by heavy flying buttresses which allowed the architects to increase the window size significantly, while the west end is dominated by two contrasting spires – a 105-metre  plain pyramid completed around 1160 and a 113-metre early 16th-century Flamboyant spire on top of an older tower. Equally notable are the three great façades, each adorned with hundreds of sculpted figures illustrating key theological themes and narratives.

Since at least the 12th century the cathedral has been an important destination for travellers. It attracts large numbers of Christian pilgrims, many of whom come to venerate its famous relic, the Sancta Camisa, said to be the tunic worn by the Virgin Mary at Christ's birth, as well as large numbers of secular tourists who come to admire the cathedral's architecture and art. A venerated Black Madonna enshrined within was crowned by Pope Pius IX on 31 May 1855.