Porto-Novo (also known as Hogbonou and Adjacé) is the official capital of the West African nation of Benin, and was the capital of French Dahomey. The commune covers an area of 110 square kilometres and as of 2002 had a population of 223,552 people.

Porto-Novo is a port on an inlet of the Gulf of Guinea, in the southeastern portion of the country. It is Benin's second-largest city, and although Porto-Novo is the official capital, the city of Cotonou is not only larger but also more important, culturally and politically: Cotonou is the seat of government. The region around Porto-Novo produces palm oil, cotton and kapok. Petroleum was discovered off the coast of the city in the 1990s, and has become an important export.

Porto-Novo was once a tributary of the Yoruba kingdom of Oyo and there continues to be a sizable Yoruba community in Porto Novo today. The city's name is of Portuguese origin, meaning "New Port." It was originally developed as a port for the slave trade.

In 1863, the British, who were active in nearby Nigeria, bombarded the city, which persuaded the Kingdom of Porto-Novo to accept French protection. The neighboring Kingdom of Abomey objected to French involvement in the region and war broke out between the two states. In 1883, Porto-Novo was incorporated into the French "colony of Dahomey and its dependencies." In 1900, it became Dahomey's capital city.