The Porto Metro is a light rail network in Porto, Portugal and a key part of the city's public transport system. Being a semi-metro, it runs underground in central Porto and above ground into the city's suburbs using low-floor tram vehicles. The first parts of the system have been in operation since 2002. It is a separate system to Porto's vintage trams.

Porto, also known as Oporto, is the second largest city in Portugal after Lisbon. It is the capital of the Porto District and one of the Iberian Peninsula's major urban areas. Porto city proper, which is the entire municipality of Porto, is small compared to its metropolitan area, with an estimated population of just 237,559 people in a municipality with only 41.42 km2 (16 sq mi). Porto's metropolitan area has around 1.7 million people (2021) in an area of 2,395 km2 (925 sq mi), making it the second-largest urban area in Portugal. It is recognized as a global city with a Gamma + rating from the Globalization and World Cities Research Network.