Ruben "Doc" Cavazos (born 1957) is an American criminal and former International President of the Mongols Motorcycle Club. His autobiography, Honor Few, Fear None: The Life & Times of a Mongol, was published by HarperCollins in June 2008.
Cavazos was raised by his padre in Highland Park, Los Angeles, California and joined the Avenues, a Mexican American street gang, at an early age before serving time in county jail. He has a license to work as a radiology technician, hence the nickname "Doc". He later became a member of the Mongols and is one of the gang's most infamous members. He has been blamed for turning the club into one of the largest criminal organizations on the West Coast of the United States during his time as President. In order to bolster the gang's ranks, he also recruited members of street gangs into the club, much to the disgust of the old school bikers. He was voted out of the club on August 30, 2008 during a meeting in Vernon, California, due to the majority of the membership believing that he was stealing from the club and provoking a war with the Mexican Mafia.