Alberto Contador Velasco (; born 6 December 1982) is a Spanish professional cyclist, one of five riders to have won all three Grand Tours of road cycling. He was the winner of the 2007 Tour de France with the Discovery Channel team. With the Astana team he has won the 2008 Giro d'Italia, the 2008 Vuelta a España and the 2009 Tour de France. He initially also won the 2010 Tour de France with this team, and the 2011 Giro d'Italia with team Saxo Bank-SunGard, only to be stripped of these titles later having been found guilty of a doping offence. After that, he won again the 2012 Vuelta a España.
Contador has been widely considered to be the best climbing specialist and stage racer in the world. Notable summit stage finishes on which he has victories include the Alto de El Angliru in the Vuelta, the Plateau de Beille in the Tour and Mount Etna in the Giro. After being widely expected to lose his tenuous lead in the 2007 Tour de France in that race's final individual time trial, Contador has become a more accomplished time trialist, with several victories in the discipline. He has earned a reputation as an all-rounder, a cyclist who excels in all aspects of stage racing which are needed for high places in the general classification.
Contador's career has been marked by doping allegations. The Operación Puerto doping case led his Astana-Würth team (a team unrelated to the current Astana team) to withdraw en masse from the 2006 Tour de France before it began. He was eventually cleared of any wrongdoing, but was also accused of doping after his victory in the race the following year. In September 2010, Contador announced that he had tested positive for clenbuterol in a control taken during that year's Tour de France, in which he finished as winner, but although he was suspended during an investigation, he was cleared by the RFEC. A review by the Court of Arbitration for Sport initially set for June 2011 was later deferred several times until February 2012, when the CAS decided that Contador be stripped from the results obtained in the 2010 Tour de France and later, which also caused him to lose his 2011 Giro d'Italia victory. He was also suspended until 5 August 2012, and his contract with Team Saxo Bank was annulled. Upon the completion of his ban, Contador rejoined the renamed Team Saxo Bank-Tinkoff Bank.