Juan Manuel Márquez Méndez (born August 23, 1973) is a Mexican former professional boxer who competed from 1993 to 2014. He is the third Mexican boxer (after Érik Morales and Jorge Arce) to become a world champion in four weight classes, having held nine world championships including the WBA (Super), IBF and WBO featherweight titles between 2003 and 2007; the WBC super featherweight title from 2007 to 2008; the WBA (Super), WBO, Ring magazine and lineal lightweight titles between 2008 and 2012; and the WBO junior welterweight title from 2012 to 2013.
In a career that spanned over twenty years, Márquez was known for being a fast and highly technical boxer who was exceptionally skilled at combinations and counterpunches, yet also willing to engage in slugfests with opponents. He was also credited for his toughness, and never lost a fight by stoppage. His most notable bouts include his four-fight saga with Manny Pacquiao and his fight against fellow Mexican Marco Antonio Barrera. Márquez is considered to be one of the greatest Mexican boxers of all time, and is ranked by BoxRec as the 30th greatest boxer of all time, as well as second best Mexican fighter of all time, pound for pound. In 2008, The Ring ranked him as the world's second best active boxer, pound for pound.