Gordon Leslie Ada AO, FAA (6 December 1922 – 25 September 2012) was an Australian biochemist best known for his seminal contributions to virology and immunology and his long leadership of the Department of Microbiology at the John Curtin School of Medical Research at the Australian National University, where Peter C. Doherty and Rolf Zinkernagel performed their Nobel winning research in his department. Both Zinkernagel and Doherty held him in high regard, and he was invited by them to attend the Nobel award ceremony and dinner in Stockholm. He died on 25 September 2012.