María Belén Barreiro Mazali (born 8 December 1999)[1] is a Uruguayan field hockey player, who plays as a defender.

Barreiro made her debut for the Uruguay U–21 at the 2021 Pan American Junior Championship in Santiago.

[2] At the tournament she won a silver medal, as well as scoring the team's only goal.

[3] Barriero made her senior international debut for Las Cimarronas in 2018, during the FIH Series Open in Santiago.

[2][4] She won her first medal with the national team in 2022, taking home bronze at the South American Games in Asunción.