Mahamadou Diarra (born May 18, 1981 in Bamako, Mali) is a Muslim, Malian footballer. A talented defensive midfielder that signed with Real Madrid in the summer of 2006. Diarra has played several international matches for the Mali national team.

He started his career with Greek side OFI Crete and Dutch side Vitesse Arnhem. He played for French club Olympique Lyonnais (Lyon) from 2002 until 2006, winning four Ligue 1 titles. Diarra was compared to top european midfielders like Patrick Vieira and Claude Makélélé. Many people who have worked with him, including former Vitesse Arnhem manager Ronald Koeman, felt that Diarra had the potential to succeed at the highest sporting level, but that he needed to learn how to control his strong temperament.

He was rated very highly by Lyon manager Gérard Houllier, who said that Diarra would not be leaving Lyon cheaply. His €40 million price tag matched the price Chelsea F.C. paid Lyon for Michael Essien in the summer 2005. Real Madrid joined in the race to sign Diarra, along with Manchester United, and on August 18, 2006 Real Madrid reached an agreement with Lyon for €26 million.

On August 22, he was unveiled at the Santiago Bernabeu by Real Madrid president Ramón Calderón, and he was assigned the number 6 shirt; Iván Helguera's prior season shirt number. At the beginning of the 2006-2007 season, Diarra was a staple player in Real Madrid coach Fabio Capello's 2-defensive midfielder system; however, a string of poor results saw Diarra relegated to the bench in favor of a new system.

Guti, a more offensive-minded midfielder replaced him, while Capello favored Brazilian Emerson in the defensive position. By mid-December, Diarra, complaining about lack of playing time, found himself a regular on the Real Madrid bench.