Piara Singh Gill (28 October 1911 – 23 March 2002) was an Indian nuclear physicist and a pioneer in cosmic ray nuclear physics. He was the first Director of Central Scientific Instruments Organisation (CSIO) of India. He was research fellow of University of Chicago (1940). He was research Professorship fellow of Tata Institute of Fundamental Research (TIFR) (1947), Officer-on-Special Duty (OSD) with the Atomic Energy Commission in New Delhi. Professor and head of the Department of Physics at Aligarh University (1949), Director of Central Scientific Instruments Organization (CSIO) (1959) and Professor Emeritus at Punjab Agricultural University (1971).