Clube Atlético Mineiro (Portuguese pronunciation: [ˈklubi ɐˈtlɛtʃiku miˈne(j)ɾu]), commonly known as Atlético or Atlético Mineiro, and colloquially as Galo (pronounced [ˈgalu], "Rooster"), is the largest and oldest professional football club based in the city of Belo Horizonte, the capital city of the Brazilian state of Minas Gerais. The team competes in the Campeonato Brasileiro Série A, the first level of Brazilian football, as well as in the Campeonato Mineiro, the top tier state league of Minas Gerais.

Atlético is the largest and oldest active football club in Minas Gerais, founded on 25 March 1908 by twenty-two students from Belo Horizonte. Despite having upper-class founders, the club immediately opened its doors to players of every social class, establishing itself as a "people's club", and becoming one of the most-supported clubs in Brazil. The club's mascot, a rooster, has been strongly associated with Atlético since its introduction in the 1930s. Over the years, the word Galo (Portuguese for "rooster") became a common nickname for the club itself. The team's regular home kit comprises black-and-white striped shirts, with black shorts and white socks.

Atlético has won the Campeonato Mineiro a record 47 times. At the national level, the club has won the Campeonato Brasileiro twice and has finished second on five occasions. It has also won two Copa do Brasil, and the Supercopa do Brasil, the Copa dos Campeões Estaduais, and the Copa dos Campeões Brasileiros once each. In international club football, Atlético has won the Copa Libertadores and the Recopa Sudamericana once each, and a record two Copa CONMEBOL; the team has also reached three other continental finals. The club has also competed in other sports throughout its history, with the futsal department becoming especially notable.

Atlético plays its home matches at the estádio Mineirão, the club has a long-standing cross-city rivalry with Cruzeiro, with matches between the two teams referred to as the Clássico Mineiro. The club also holds a local rivalry with América Mineiro, and an interstate one with Flamengo. Atlético has the eighth most valuable brand in Brazil, worth R$515.5 million (€143 million) as of 2016, and ranks seventh in the country in terms of turnover, generating R$244.6 million (€62.2 million) in 2015.

Atlético is currently building a new stadium, the Arena MRV, which will have a capacity of over 48,000 spectators. Its inauguration is scheduled for the first quarter of 2023.