[6] On 5 November 2023, Flamengo debut the goalkeeper's third kit for the 2023 season in a Campeonato Brasileiro Série A match against Fortaleza.

[citation needed] Supplier: Adidas Sponsors: Banco BRB (Main sponsor) / Mercado Livre (Back of the shirt) / Assist Card (Lower back) / Pixbet (Shoulder) / Sil Cabos (Sleeves) / TIM (Numbers) / ABC da Construção (Shorts) On 14 November 2022, Filipe Luís extended his contract for another year until 31 December 2023.

[7] On 25 November 2022, head coach Dorival Júnior announced he and Flamengo mutually decided to not extend his contract for another season.

[24][25] Also on 12 January the club announced that Guillermo Varela, previously on loan, signed a pre contract for a permanent deal starting at the end of his constract with Dynamo Moscow on 1 July.

[26][27] Due to calendar conflicts with FIFA Club World Cup the Campeonato Carioca started earlier for Flamengo with the matchday 5 match against Audax Rio being moved to 12 January.

[29] Vítor Pereira debuted as Flamengo head coach in the second match of the season, a 4–1 win against Portuguesa on 15 January.

[31] Against Bangu on 24 January, once again Flamengo was managed by Mario Jorge and played with members of youth team plus Rodrigo Caio, still recovering from injury.

[33] After a battle between Olympique Lyonnais and Wolverhampton Wanderers to sign João Gomes, the midfielder finally transferred to the English side on 26 January.

[38][39] Four days later on 11 February, Flamengo played the third place match against Egypt club Al Ahly winning 4–2 with Pedro and Gabriel Barbosa each scoring a brace.

Ironically Giorgian de Arrascaeta missed the only penalty kick in the shootout as Independiente del Valle lifted the trophy for the first time.

[45] On 5 March, Flamengo lost the first Clássico dos Milhões of the season 1–0 against Vasco da Gama, the only goal was scored by José Luis Rodríguez.

On 13 March the clubs played the first leg in a match full of defensive mistakes Vasco da Gama opened the score early, but Flamengo managed to come from behind winning 3–2, including a beautiful Giorgian de Arrascaeta's goal from a long range.

Flamengo faced Fluminense for the second year in a row and had a solid match winning 2–0, Ayrton Lucas and Pedro scored the goals.

[51] Despite a strong finals first leg, on the second fixture Flamengo played a terrible match being dominated by Fluminense and losing 4–1 on 9 April.

With the series of bad results in the beginning of the season club's directors decided to sack Vítor Pereira on 11 April, appointing Mário Jorge as caretaker for the following matches.

[57] The first match under Jorge Sampaoli control was played on 19 April against Chilean club Ñublense, a Copa Libertadores fixture at Maracanã Stadium.

[60][61] On 5 June, Flamengo and Vasco da Gama played another Clássico dos Milhões derby, this time in the 2023 Campeonato Brasileiro Série A at Maracanã Stadium.

[67] The second leg was played on 12 July at Ligga Arena, Flamengo won 2–0 and advanced for the Copa do Brasil semi-finals for the third time in a row.

[69] On 8 July, Flamengo and Palmeiras met at Allianz Parque and draw 1–1,[70] the match was marked by the fight on the streets between supporters from both clubs.

[72] Weeks later on 25 July, Rio de Janeiro police arrested Jonathan Messias Santos da Silva after he was identified as the one who threw the glass bottle.

[73] Disappointed with losing space in the team and playing few minutes under the command of Jorge Sampaoli, Arturo Vidal negotiated a contract termination with Flamengo on 10 July.

[74] On 22 July, in a 1–1 draw against América Mineiro, Giorgian de Arrascaeta became the first non-Brazilian player in club's history to reach 100 Campeonato Brasileiro Série A matches.

[75] During the second half Pedro refused to warm-up and after the match was assaulted by fitness coach Pablo Fernández with a punch in the mouth in the locker room.

[78] On 30 July, Flamengo accepted Crystal Palace's offer for Matheus França, he moved to the Premier League club for a €20m transfer fee plus future bonus clauses.

Transfer canceled Source: Playmaker, Soccerway, FBRef Players in italics have left the club before the end of the season.