Vila Nova de Gaia, or simply Gaia, is a city and a municipality in Porto District in Norte Region, Portugal. It is located south of the city of Porto on the other side of the Douro River. The city proper had a population of 178,255 in 2001. The municipality had a total population of 302,295 inhabitants (2011), making it the most populous municipality in Norte Region. Gaia along with Porto and 12 other municipalities make up the commonly designated Porto Metropolitan Area.

The city contains many cellars (locally known as "caves") where port wine is stored and aged. These cellars have become a major tourist attraction.

Vila Nova de Gaia is the Portuguese municipality with the biggest number of Blue Flag beaches in 2009 and in 2010: 17 beaches along 17 km of seaside. Some popular beaches are: Miramar, Granja, Aguda, Valadares, Francelos, Madalena and Canidelo. Praia da Granja is a FEE Blue Flag beach in the parish of São Félix da Marinha. This area was a farm in the 18th century belong to the Grijó Monastery and used as a rest place of monks and priests.