Gregory (Gary) Koshnitsky (6 October 1907, Kishinev - 17 September 1999, Australia) was an Australian chess master.
Born in Kishinev, Bessarabia (then Russia, now Moldova), he emigrated in his youth to Australia.
He was Australian Champion in 1933 and 1939 (with Lajos Steiner), and won three Queensland titles, seven New South Wales titles, and one South Australian title (1966). His last win was something of an anniversary, as he won his first tournament in Australia, the Queensland championship in 1926.
Koshnitsky was awarded the IMC title (International Master of Correspondence Chess) in 1972. He was appointed Honorary Member of FIDE in 1993.
He was the author of the book Chess Made Easy (with Cecil Purdy).
He was the father-in-law of Ngan Phan-Koshnitsky.