Homi Nusserwanji Sethna (24 August 1923 – 5 September 2010) was an Indian nuclear scientist and a chemical engineer, gaining international fame as the Chairman of the Atomic Energy Commission (India) during the time when the first nuclear test, codename Smiling Buddha in Pokhran Test Range in 1974 was conducted.
He was the primary and central figure in India's civilian nuclear program as well as the construction of nuclear power plants.
He was awarded the second highest civilian award the Padma Vibhushan in 1975, by Government of India.
Earlier in his career, he had full technical responsibility for setting up of the Thorium extraction plant at Alwaye, Kerala India, for separation of rare earth from monazite sands.