John Todd (May 16, 1911 – June 21, 2007) was a professor of mathematics and a pioneer in the field of numerical analysis.
He was born in Carnacally, County Down, Ireland, and grew up near Belfast. He received his BSc degree from Queen's University in 1931, and went to St. John's College at Cambridge University.
He worked at King's College in London, where he met Olga Taussky, a matrix and number theorist. They were married in 1938.
He worked for the British Admiralty during World War II. One of Todd's greatest achievements was the preservation of the Mathematical Research Institute of Oberwolfach in Germany at the end of the war.
In 1945 the Todds emigrated to the United States and worked for the National Bureau of Standards. In 1957 they joined the faculty of California Institute of Technology in Pasadena, California.
John Todd retired from the faculty, and in May, 2001 was honored by a symposium at Caltech in honor of his 90th birthday. He died at his home in Pasadena, California on June 21, 2007.