Mateo Barreiros Reyes (born 14 December 2000) is a Brazilian professional tennis player who was born in Ecuador. He has a career-high ATP singles ranking of No. 595, achieved on 29 July 2024 and a best doubles ranking of No. 310, achieved on 16 June 2025.
Barreiros Reyes has won one ATP Challenger doubles title at the 2025 Brazzaville Challenger, with countryman Paulo Saraiva dos Santos.
In July 2025, he was given a provisional suspension after failing an anti-doping test at an ATP Challenger event in Colombia in May that year.