The 2013 Campeonato Brasileiro Série A was the 57th edition of the Campeonato Brasileiro Série A, the top-level of professional football in Brazil. Fluminense came in as the defending champions, having won the title in the 2012 season. On 13 November 2013, Cruzeiro won the title for the club's third time.

For the first time since the league adopted the 20-team, double round-robin format, all four teams promoted from Série B survived.

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For the eleventh consecutive season, the tournament was played in a double round-robin system. In a fashion similar to its second title in 2003, Cruzeiro led the rankings for most of the tournament, declared champion in the fifth to last round. The bottom four teams, Fluminense, Vasco, Ponte Preta and Nautico were relegated to play in the Campeonato Brasileiro Série B in the 2014 season.

The tournament had a one-month interruption between June 9 and July 6 due to the 2013 FIFA Confederations Cup, which took place in Brazil.

Although Flamengo finished the championship just above the relegation positions, it was punished by the Superior Court of Sport Justice for irregularly calling in a player during their final match against Cruzeiro. Flamengo playedAndré Santos, who was suspended due to receiving a red card at a previous Copa do Brasil match.^[2] The team lost four points - three for the irregular usage of a player and a fourth one from the tie in the game against Cruzeiro. With the punishment, Flamengo was going to be relegated.^[2] However, the day after Flamengo's game, Portuguesa also irregularly called in a player against Grêmio: Héverton. The team also lost four points - three for the irregular usage of a player and a fourth one from the tie in the game against Grêmio. Portuguesa, who had been below Flamengo in the table before both teams' punishments, ended up being relegated instead of Flamengo. With both punishments, Fluminense FC also managed to finish the championship above the relegation positions and was spared from having to compete in the following year's second division.^[2] Portuguesa's irregular usage of a player raised many suspicions, both from Flamengo's - who had also used an irregular player the day before - and Fluminense's side. This relegation was the start to a downhill turn for Portuguesa, as the team was relegated to the Brazilian Third Division - Série C the following year.