Ignacio Bonillas Fraijo (1 February 1858 – 23 June 1942) was a Mexican diplomat. He was a Mexican ambassador to the United States and held a degree in mine engineering from the Massachusetts Institute of Technology. He was tapped by President Venustiano Carranza as his successor in the 1920 presidential elections, but the revolt of three Sonoran revolutionary generals overthrew Carranza before those elections took place.