Sebastián Acuña Murillo (born 25 June 2002) is a Costa Rican professional footballer who plays as a defensive midfielder for Liga FPD club Deportivo Saprissa and the Costa Rica national team.

Acuña began his career with San Carlos making his professional league debut on 10 June 2020 playing the full match in a 5–2 win over Municipal Grecia.

[1] In December 2024, after nearly 11 appearances in all competitions for San Carlos, Acuña agreed to join Deportivo Saprissa on a four-year deal.

[2] Acuña was part of the Costa Rica U23 that earned a silver medal in the football at the 2023 Central American and Caribbean Games.

Acuña made his senior international debut for Costa Rica on 8 September 2023, playing the first half of a friendly against Saudi Arabia.