Felix A. Sommerfeld (May 28, 1879 – ?) was a German secret service agent in Mexico and the United States between 1908 and 1919. He was chief of the Mexican secret service under President Francisco I. Madero, worked as a diplomat and arms buyer for Venustiano Carranza and Francisco "Pancho" Villa, and ran the Mexican portion of Germany's war strategy in North America between 1914 and 1917.