Ruby Duncan worked as a typist in an importer's office. She campaigned, with Millicent Preston Stanley, for change in the law to give mothers equal guardianship of children. She was very involved with Housewives' Progressive Association during period that membership grew from hundreds to 80,000. She also worked for alleviation of Depression distress among unemployed women, and on a scheme for placing women on small land holdings in buses with kitchenettes and verandahs for home.

She was the first President, and a life Vice President, of the League of Women Voters, which organization marked her 90th birthday with a reception in her honour. She died in Armidale, aged 98.

Sources used to compile this entry: Sydney Morning Herald, 3 March 1972, 7 February 1981; Parliamentary scrapbook, "Candidates who offered themselves at the General Election on 11th June 1932", NSW; Parliamentary Archives.