Alexander Mejía Sabalza (born 11 July 1988) is a Colombian footballer who plays as a midfielder for Club Libertad. He is described by FIFA's official website as "a linchpin noted for his ability to tidy up mistakes, rob possession and track down and pressurise opponents".
Mejía made his professional debut for Deportes Quindío in 2005, where he played for seven years, including a loan spell at Once Caldas. In 2012, he joined Atlético Nacional and won both the Copa Colombia and the Superliga Colombiana in his first season. In the following seasons, Mejía helped Nacional to three consecutive Colombian league titles, becoming team captain after the departure of Macnelly Torres.
Mejía finished his loan at Nacional in June 2016. He was then transferred to León in the Liga MX for the Apertura 2016. However, as a part of the deal, he was able to stay with Nacional until after the Medellín club had finished its campaign in the Copa Libertadores.