Ian Robert Cathie (24 October 1932 – 25 October 2017) was an Australian politician. Born in Melbourne, to printer George Mitchell Cathie and Sybil Balding, he attended state schools, Wesley College, then the University of Melbourne, where he studied teaching. On 5 January 1957 he married Christine Watson, with whom he had four children; he married again on 3 July 1976 Jean Germain, an industrial nurse. He was president of the Peninsula Victorian Teachers Union in 1959 and taught at Frankston and Mordialloc-Chelsea High Schools, as well as serving on the council of Monash University from 1977 to 1982.