Clube de Regatas do Flamengo (Brazilian Portuguese: [ˈklubi dʒi ʁeˈɡataʒ du flaˈmẽɡu]; English: Flamengo Rowing Club), commonly referred to as Flamengo, is a Brazilian sports club based in Rio de Janeiro best known for their professional football team.

The club was first established in 1895 as a rowing club and played their first official match in 1912. Flamengo's traditional uniform featured red and black striped shirts with white shorts, and red and black striped socks. Flamengo had typically played their home matches in the Maracanã, the national stadium of Brazil, since its completion in 1950, with some exceptions in recent years. Since 1969, the vulture (Portuguese: urubu) has been the most recognized mascot of Flamengo.

Flamengo established themselves as one of Brazil's most successful sports clubs in the 20th century during of the era of state leagues in Brazil when they captured several Campeonato Carioca (Rio de Janeiro state league) titles prior to the establishment of the first Brazilian national football league in 1959. Since then, they have remained successful in Brazilian football, having won 6 Campeonato Brasileiro Série A (including the Copa União of 1987), 3 Copa do Brasil, and a record 35 Campeonato Carioca. They are one of five clubs to have never been relegated from the Brasileirão. In South American and worldwide competitions, the club's highest achievements are their conquests of the 1981 Copa Libertadores and Intercontinental Cup against Liverpool, led by the club's most iconic player Zico. Flamengo's fiercest and longest-standing rivalries are with the other "Big Four" of Rio de Janeiro: Fluminense, Botafogo and Vasco da Gama.

Flamengo is the most popular club in Brazil, with over 30 million supporters as of 2018. As of 2017, it is also Brazil's richest football club with an annual revenue of R$648.0 million (€163.04 million) and a valuation of over R$1.69 billion (€425.21 million).