Major General Thomas Francis Farrell (3 December 1891 – 11 April 1967) was the Deputy Commanding General and Chief of Field Operations of the Manhattan Project, acting as executive officer to Major General Leslie R. Groves, Jr.Farrell graduated from Rensselaer Polytechnic Institute with a degree in civil engineering in 1912. During World War I, he served with the 1st Engineers on the Western Front, and was awarded the Distinguished Service Cross and the French Croix de guerre.