The Sons of Silence Motorcycle Club (SOSMC) is an international outlaw motorcycle club. Founded in Niwot, Colorado in the United States in 1966, the club has a membership of over 250, with 35 chapters based in 12 U.S. states and in Germany. The Sons of Silence are the sixth-largest motorcycle club in the world, behind the Hells Angels, the Bandidos, the Outlaws, the Pagans and the Mongols.