Mark "Papa Frisco" Guardado (1962 – September 3, 2008) was an American mobster and President of the Hells Angels Motorcycle Club's San Francisco chapter. He was also an advisor for the television show Sons of Anarchy, which follows an outlaw motorcycle club.

On February 10, 2008, Guardado allegedly beat up a man in Petaluma, California but died before he could be sentenced. According to witnesses, he bumped into a bar patron at McNear's Saloon & Dining House and created a scene. The man then fled but was ambushed by other Hells Angels members outside and beaten up. Guardado was charged with battery and Jonathan Nelson, Vice-President of the Sonoma County chapter of the Hells Angels, was charged with felony battery in the incident. In March, 2010, Jonathan Nelson was acquitted of felony assault and gang charges related to the McNear's altercation by a Sonoma County jury. The jury found that the Hells Angels were not a criminal street gang under California law. In July 2008, Guardado was arrested on suspicion of possessing magic mushrooms after the Hells Angels clubhouse was raided in San Francisco. During the 1990's, he also served time in prison in Massachusetts for assault.

Guardado was murdered in San Francisco's Mission District on September 2, 2008. He got into a fight with a man in a bar and was shot dead as he left at around 10:30 p.m. The San Francisco Police Department then issued a $5 million arrest warrant for Christopher Ablett, a member of the Mongols Motorcycle Club, in connection with the murder. Ablett turned himself in to authorities in Bartlesville, Oklahoma on October 4 later that year.

Around 2,000 Hells Angels members from all over the United States, as well as Australia, Canada and Germany, attended his funeral, which was held in Daly City, California on September 15