Sam Baker (died 1878) was an American counterfeit courier who was affiliated with Austin Greer's counterfeiting ring in San Francisco during the 1870s. In 1878, he and Randall Kenney were intercepted by United States Secret Service agents Edmund Mosley and Joshua Donaldson while transporting some of Greer's money by wagon, and, while they attempted to surprise and kill the two agents, Mosley shot Baker dead after Baker killed Donaldson, and Mosley wounded Kenney and took him in for interrogation.