Marcus Vinicius Oliveira Alencar (born 7 April 2003), better known professionally as Marquinhos, is a Brazilian professional footballer who plays as a winger for Brazilian Club Fluminense, on loan from Premier League club Arsenal and the Brazil national team.
Marquinhos made his professional debut for São Paulo on 11 July 2021, coming on as a 78th minute substitute in a 1–0 Série A home win against Bahia.
On 13 June 2022, Marquinhos signed for English club Arsenal on a long-term contract.
However, fellow Premier League side Wolverhampton Wanderers were considering taking legal action against both Marquinhos and São Paulo, as Marquinhos had reportedly signed a pre-contract agreement with them prior to joining Arsenal.
On 8 September, Marquinhos made his competitive debut for Arsenal in a 2–1 UEFA Europa League away win over Zürich, where he scored his first goal both for the club and in European competition, and also registered an assist for Eddie Nketiah in the same match.
He made his Premier League debut on 18 September, coming on as a late substitute for Bukayo Saka in a 3–0 win at Brentford.
His first appearance at the Emirates Stadium came on 6 October, in the Europa League game against Bodø/Glimt.
On 31 January 2023, Marquinhos joined Championship club Norwich City on loan for the rest of the 2022–23 season.
He made his debut on 25 February, scoring once and also providing an assist for Gabriel Sara in Norwich's 2–0 win against Cardiff City.
Marquinhos received the first red card of his senior career on 15 March in Norwich's draw at Huddersfield Town after he appeared to elbow Josh Ruffels.
However, Norwich successfully appealed the decision, and the three-match ban was overturned.
On 12 August 2023, Ligue 1 side Nantes announced the signing of Marquinhos on a season-long loan from Arsenal, with no future option to make the move permanent.
On 12 January, he was recalled by Arsenal.
On 15 February 2024, Marquinhos returned to his native Brazil, joining Fluminense on loan until January 2025.
