Lagos is a municipality at the mouth of Bensafrim River and along the Atlantic Ocean, in the Barlavento region of the Algarve, in southern Portugal. The main town of Lagos (which includes only the parish of São Sebastião e Santa Maria) has a population of approximately 22,000. Typically, these numbers increase during the summer months, with the influx of visiting tourists and seasonal residents. While the majority of the population lives along the coast and works in tourism and services, the inland region is sparsely inhabited, with the majority of the people working in agriculture and forestry.

Lagos is one of the most visited cities in the Algarve and Portugal, due to its variety of tourist-friendly beaches, rock formations (Ponta da Piedade), bars, restaurants and hotels, renowned for its vibrant summer nightlife and parties.[citation needed] Yet, Lagos is also a historic centre of the Portuguese Age of Discovery, frequent home of Henry the Navigator, historical shipyard and, at one time, centre of the European slave trade. In 2012, travel website TripAdvisor, classified Lagos as the number one travel destination, on a list of "15 destinations on the rise" worldwide.

Lagos, Nigeria, may have been named after it, since, at the time of the 15th century, Lagos, Portugal, was the main centre of Portuguese maritime expeditions down the African coast.