Patras (Greek: Πάτρα, romanized: Pátra [ˈpatra]; Katharevousa and Ancient Greek: Πάτραι; Latin: Patrae) is Greece's third-largest city and the regional capital of Western Greece, in the northern Peloponnese, 215 km (134 mi) west of Athens. The city is built at the foot of Mount Panachaikon, overlooking the Gulf of Patras.

As of the 2011 census, the city of Patras has a population of 167,446 and the municipal unit has 170,896 inhabitants; the municipality has 213,984 inhabitants. The population of its functional urban area was 217,555 in 2011. The core settlement has a history spanning four millennia. In the Roman period, it had become a cosmopolitan center of the eastern Mediterranean whilst, according to the Christian tradition, it was also the place of Saint Andrew's martyrdom.

Dubbed as Greece's 'Gate to the West', Patras is a commercial hub, while its busy port is a nodal point for trade and communication with Italy and the rest of Western Europe. The city has three public universities, hosting a large student population and rendering Patras an important scientific centre with a field of excellence in technological education. The Rio-Antirio Bridge connects Patras' easternmost suburb of Rio to the town of Antirrio, connecting the Peloponnese peninsula with mainland Greece.

Every year, in February, the city hosts one of Europe's largest carnivals. Notable features of the Patras Carnival include its mammoth satirical floats and balls and parades, enjoyed by hundreds of thousands of visitors in a Mediterranean climate. Patras is also famous for supporting an indigenous cultural scene active mainly in the performing arts and modern urban literature. It was European Capital of Culture in 2006.