Basanti Dulal Nag Chaudhuri (6 September 1917 – 25 June 2006) was an Indian Nuclear scientist and academic, and Scientific Advisor to the Ministry of Defence, Government of India. He is known as one of the pioneers of nuclear physics in India. While serving as the Director General to the Defence Research and Development Organisation (DRDO), he played influential role in Pokhran-I (Smiling Buddha), India's first successful Nuclear bomb test on 18 May 1974. He also initiated the first feasibility studies on India's ballistic missile program.