The 2009 Copa Libertadores de América (officially the 2009 Copa Santander Libertadores de América for sponsorship reasons) was the 50th edition of the Copa Libertadores de América, CONMEBOL's premier annual international club tournament.

The tournament was won by Argentine club Estudiantes de La Plata, who achieved their fourth Copa Libertadores title and first in 39 years.

Estudiantes earned a berth to play in 2010 Recopa Sudamericana and in the 2009 FIFA Club World Cup but lost both titles to LDU Quito and Barcelona respectively.

If two or more teams are equal on points, the following criteria will be applied to determine the rankings in the group stage: For the first stage, round of 16, quarterfinals, and semifinals, the fourth criterion is replaced by a penalty shootout if necessary.

The last four stages of the tournament (round of 16, quarterfinals, semifinals, and finals) form a single-elimination tournament, commonly known as a knockout stage.