William G. Sebold (Wilhelm Georg Debrowski; 10 March 1899 in Mülheim, Germany – 16 February 1970 in Walnut Creek, California) was a United States citizen when he visited Germany and was coerced into becoming a spy. He informed the American Consul General in Cologne before leaving Germany and became a double agent for the FBI. With the assistance of another German agent, Fritz Duquesne, he recruited 32 agents that became known as the Duquesne Spy Ring.