Robert Mahony (3 October 1872 – 8 February 1961) was an Irish-born Australian politician.
He was born on 3 October February 1872, in Cork to shipwright William Mahony and Bridget Manning.
The family migrated to Sydney in 1877 and Robert was educated at a Balmain convent before becoming a boilermaker.
In July 1895, he married Margaret Jane Mahony, with whom he had eight children.
From 1921 to 1961, he was a Labor member of the New South Wales Legislative Council, serving as party whip from 1922 to 1961.